According to the law of conservation of momentum, the momentum of a system remains constant if no external force acts on it.

1) When the shot is fired from a cannon and explodes in mid-air, no external force acts on it, and therefore, the linear momentum is conserved.

2) When the cannon explodes, the chemical potential energy stored in the explosives gets converted to kinetic energy due to the velocity acquired.

Therefore, when a shot is fired from a cannon and explodes in mid-air, the momentum will remain constant but kinetic energy will increase.

Explanation:

Early Physics Concept

The formula for conversion is,

km/h = (18/5) x m/s.

Therefore,

15 m/s = 15 x (18/5)

= 54 km/h.

Explanation:

• As the Body reached to its initial Position its mean Displacement is zero.
• For Distance = Circumference = n (2 π r) 

Here: r = 3R 

and :-  n= 2

Distance = 2 ( 2 π (3R)

Distance = 12 π R

Explanation:

u(initial velocity) = 19.6 m/s

at highest point v(final velocity)=0

using v=u + at

0 = 19.6 - 9.8 * t

t=19.6/9.8= 2s (time  to reach max height)

Explanation:

From Newton'a second law, force $F=ma$

$⟹$  F / a ​= m

Thus ratio of force and acceleration is equal to mass of the body.

Explanation:

If the speed of a straight line moving object changes, its speed is called Changed.

• Uniform speed:

  • An object is said to be in uniform speed when the object covers equal distance in equal time intervals.

• Variable speed:

  • ​An object is said to be in variable speed when the object covers a different distance at equal intervals of times.

• Average speed:

  • ​Average speed is defined as the uniform speed which is given by the ratio of total distance traveled by an object to the total time taken by the object.

• Instantaneous speed:

  • When an object is moving with variable speed, then the speed of that object at any instant of time is known as instantaneous speed.

Explanation:

Suppose the acceleration is $a$ then using the second equation of motion, s = ut + 1/2​ at^2

and putting $t=2sec$ and $u=10m/s$ 

we get $20=10\times 2+a\times 2$

or $a=0$ that is $uniform$ motion

In completing 1 revolution, distance covered  $=2\pi R$ and displacement = 0,

for half Revolution:
distance covered  $=\pi R$
and displacement = 2R

Explanation:

When the particle is in motion for some time, the speed and distance covered cannot be zero because the particle is moving. However, the displacement can be zero because the particle can come back to its initial position. In this case, the final position of the particle coincides with its initial position such that displacement, which is a distance with direction, becomes zero.

use the conservation of energy, all the kinetic energy that it has at the bottom is equal to the potential energy it will have at the top. Quick and dirty assumption that g = 10 m/s²

mv²/2 = mgh

v²/2 = gh

h = v²/2g

h = (20 m/s)² / (2 × 10 m/s²)

h = (400 m²/s²) / (20 m/s²)

h = (400/20) (m² × s²) / (m × s²)

h = 20 m

Explanation:

PICTURE FOR MOTION AND FORCE, different Motion Explained

Explanation:

Explanation:

• Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force. This postulate is known as the law of inertia.
• Hence a force is not required to keep the particle moving with uniform speed

Explanation:

Initial linear momentum of the system: P_i =mv=50 x 10 =500 kg m/sec
Final Momentum of The System: P_f = (M + m)V

P= (50+20)V
P= 70V
According to Law of Conservation of Momentum:
Final Momentum = Initial Momentum
70V = 500
V= 500/70 = 7.1 km/h

Explanation:

Thus, the particle will be back at it's initial position after 2 minutes. 
Thus, $|displacement|=0\; so\; the\; ratio\; will\; Also\; Zero$

The slope of the velocity time graph represents the acceleration (or deceleration) of the object. If the slope is changing, either increasing or decreasing, that means the acceleration is changing.

Curtailment is an imprecise term. But, in general yes. A decreasing slope means the object is decelerating at an increasing rate.

Slope of Horizontal Line: Zero

Slope of Vertical Line: Undefine / Infinity

If the slope of a displacement-time graph is zero, it means the displacement is constant over time.

Since velocity is the rate of change of displacement with respect to time, a constant displacement indicates that there is no change in displacement. Therefore, the velocity is zero.

The picture below shows a velocity - time graph
for an object with a velocity that decreases at a constant rate.

The straight line sloping downwards in the graph above
shows that the objects velocity is decreasing as time goes by.
This is called negative acceleration.

The straight line shows that it is constant negative acceleration.
The slope of the line shows
1. the acceleration is negative because the line slopes downwards
2. how fast the negative acceleration is.
The greater the slope, the faster the acceleration is.

Explanation:

Acceleration $=0$, Velocity $=$ Speed $=$ constant
As the position of particle changes with time so position vector is changing.

Explanation:

• The direction of acceleration is determined by the general principle that if an object is slowing down, the acceleration is in the opposite direction of the motion.
• Hence, with negative acceleration, the velocity of a body decreases.
• The negative sign of acceleration shows that the velocity of the body is decreasing per unit of time.

Explanation:

It is a straight line path hence the displacement = distance. Particle may not reverse the direction of motion due to constant acceleration. Average velocity is equal to average speed due to linear motion. Because object is accelerating, i.e. changing velocity with time, the average velocity is not equal to instantaneous velocity.

Explanation:

Explanation:

For an object moving in uniform circular motion, the direction of the instantaneous acceleration vector is directed radially inward, perpendicular to the tangential velocity.

For motion with uniform velocity, magnitude of displacement = distance

Explanation:

graph between velocity and time is a straight line which indicates that the slope is zero$.$ Normally slope of velocity$-$time graph is acceleration but when it approaches a particular point then it becomes instantaneous acceleration$.$

Given that the time-displacement graph of a particle is parallel to the time-axis. That means if the distance-time graph of the object is parallel to the time axis then the particle has not covered any displacement with change in time. i.e. the particle is at rest.

So the change of displacement of the particle with respect to time is zero so the velocity of the particle will be zero.

$P_b\text{represents momentum of ball (before hitting)}$
$P_b=5.0kg\cdot \frac{\mathrm{m/}}{s}$
$P_a\text{represents momentum of ball (after hitting)}$
$P_a=-5.0kg\cdot \frac{\mathrm{m/}}{s}$

$\Delta P:\text{change of momentum}$

$\Delta P=P_a-P_b$
$\Delta P=-4.0-4.0$

$\Delta P=-10kg.\frac{\mathrm{m/}}{s}$

Explanation:

• Time rate of change of linear momentum represents force and
• time rate of change of angular momentum represents torque.

Derivation:

Initial momentum P¹ = m × u

Final momentum P² = m × v

According to question,

dP/dt (rate of change of momentum) = (P² - P¹)/t

= m ( v - u ) / t

= m a

= Force

So, rate change of momentum is equal to Force.

Explanation:

When distance is proportional to time, the ratio of distance and time remains constant. This means that in equal time intervals, the particle is travelling equal distances. So clearly the speed of the particle remains constant.

Explanation:

Retarded motion is deceleration which implies negative acceleration, thus the slope of the velocity time graph for retarded motion is negative.

Explanation: 

On a velocity–time (v–t) graph, slope = Δv/Δt = acceleration .

A negative slope means that over a positive time interval (Δt > 0), the change in velocity (Δv) is negative (the line is falling).

So the acceleration is negative.

Physically, negative acceleration means the acceleration vector points opposite to the chosen positive direction—e.g., if you’re moving “forward,” a negative acceleration slows you down.

(Sometimes called “deceleration,” though strictly deceleration only refers to a decrease in speed, whereas negative acceleration could also speed you up in the reverse direction.)

Explanation

horizontal initial velocity of Ball will be same as that of Bus but if Ball lands in front of her and She faces engine means Bus has traveled more distance than the Ball. so Bus must be accelerating otherwise if Bus was with constant velocity then Ball will come back to the boy, or moving backward with de-acceleration.

Explanation:

In case of projectile motion the vertical component of particle's velocity changes continuously because of the force acting in vertical direction which is its own weight ($mg$).

But in the horizontal direction as there is no force acting on the
object ; its horizontal velocity remains constant

The acceleration is the rate of change of velocity. Any change in velocity – with magnitude or direction – will result in acceleration.
Therefore, in the given case, there exists no acceleration or speed variation. Also, the speed will not be zero.
The acceleration of the particle in motion will be zero during a uniform velocity.

Explanation:

When displacement is zero, particle may be at rest, therefore, distance travelled = 0.

Again, when displacement is zero, final position coincides with the initial position, distance travelled is not zero.

Explanation:

According to Newton's third law, if the table exerts $40N$ force on the block, the block will also apply same force on the table. As $9.8N<40N$, the net force is in upward direction and thus, the block has an upward acceleration

NOTE: On This concept Similar MCQs were in NMDCAT 2021 but this is not Exact statement but the concept is same.

Explanation:

If two particles start from rest simultaneously and are equally accelerated, they will have the same acceleration and will move together with the same velocity at all times.

Therefore, the relative velocity of one with respect to the other will be:

The picture below shows a velocity - time graph
for an object with a velocity that decreases at a constant rate.

The straight line sloping downwards in the graph above
shows that the objects velocity is decreasing as time goes by.
This is called negative acceleration.

The straight line shows that it is constant negative acceleration.
The slope of the line shows
1. the acceleration is negative because the line slopes downwards
2. how fast the negative acceleration is.
The greater the slope, the faster the acceleration is.

The picture below shows a velocity - time graph
for an object with an acceleration that increases.

The curve in the above graph shows that the
acceleration is not constant because the slope is getting steeper.
It is changing acceleration that increases as time goes by.

Explanation:

Uniform acceleration implies constant change of velocity with time, thus a straight slanting velocity-time graph that passes through the origin (from rest) but parallel to neither the time axis nor the velocity axis.

Explanation:

Concept is change in velocity = 4 - 3 = 1 

And total time = 0.5

Acceleration = 1/0.5 = 2

The acceleration of a moving object can be found from Slope of Velocity time graph

The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts.

Vi = 0;    a = 9.8 m/s2;    t = 3s

From s = v₁t + (1/2)at²

s = (1/2) * 9.8 * 3² = 44.1 m.

Explanation:

Rate of change of Momentum = Force

When a projectile is rising up, due to gravity the ball's vertical component of velocity continuously start decreasing because ball is travelling against the gravity . Now, at the highest point of a projectile path , the velocity in the vertical direction becomes zero.

Explanation: