HARD
Earn 100

Using second law of motion, derive the relation between force and acceleration.

Important Questions on Laws of Motion

EASY
An object of mass 10 gm is moving with an acceleration of 10 m/s2. Force acting on the object will be:
EASY

In a two body collision, the momentum is varying with time as shown in graph. The instantaneous force is maximum at: 

Question Image

EASY

The variation in momentum with time, for a body under collision is shown in figure. The maximum & minimum instantaneous forces are respectively on these points:

Question Image

EASY

Read the following statements and choose the correct option:
Statement: Newton's second law of motion gives the measurement of force. 
Reason: According to Newton's second law of motion, force is directly proportional to the rate of change of momentum. 

MEDIUM
Figure shows the velocity versus time graph for a block of mass 50 g sliding on a rough floor. The average rate at which energy dissipates (in Js-1) due to the force of friction is:  
Question Image
EASY
A machine gun fires a bullet of mass 40 gram at a speed of 1200 m s-1. The man holding it can exert a maximum force of 144 N on the gun. How many bullets can he fire per second at the most?
EASY

A force ‘F’ is applied on one end of a rope of length ‘a’. P and Q are two points of length ‘b’ from nearest end. The ratio of tensions in string at P & Q is :

Question Image

MEDIUM

The velocity-time graph of a ball of mass 20 g moving along a straight line on a long table is given in figure.The force exerted by the table on the ball to bring it to rest is :

Question Image

HARD

A particle of mass 0.3 kg is subjected to a force F = Kx with K = 15 N/m, what will be its acceleration if it is released from a point x = 20 cm.

EASY
A small block of material having relative density 13 is immersed in a liquid and released. The block starts moving upwards with an acceleration a. The value of a is :(g is the acceleration due to gravity)
MEDIUM
A diwali rocket is ejecting 0.05kg of gases per second at a velocity of 400 m s-1. The accelerating force on the rocket is
EASY

Two similar trucks are moving with the same velocity on a road. One of them is loaded while the other is empty. Which of the two will require a larger force to stop it?

MEDIUM

A dynamometer D is attached to two masses m1=3 kg and m2=5 kg. Forces of f1=9 N and f2=25 N are applied to the masses as shown.

Question Image

The dynamometer will read :

MEDIUM
A particle having a mass 0.5 kg is projected under gravity with a speed of 98 m sec-1 at an angle of 60°.  The magnitude of the change in momentum (in N sec) of the particle after 10 seconds is g=9.8 m s-2
EASY

What force is required to produce an acceleration of 2 m s-2 a body of mass 10 kg?

MEDIUM
Acceleration is inversely proportional to mass when _____ (Velocity / Force) is constant.
EASY

What is the direction of acceleration?