## Sample Test on Force and laws of Motion

- Write the Newton’s first law of motion? 1
- Explain why some of the leaves may get detached from a tree when w vigorously shake the branch. 1
- What is the momentum of an object of mass m, moving with a velocity v? 1
- Why is it advised to tie the luggage kept on the roof of a bus with a rope. 1
- Why a fielder a pulls his hands gradually with the moving ball while holding a catch. 1
- What is Inertia? 1
- Write the effects of forces? 2
- What is the thrust needed to fire a 350 kg rocket straight up with an acceleration of 8m/s
^{2}2 - Mathematically prove the law of conservation of momentum? 3
- A constant force acts on an object of mass 5 kg for a duration of 2 s. It increases the object’s velocity from 3 m s
^{–1}to 7 m s^{-1}. Find the magnitude of the applied force. Now, if the force was applied for a duration of 5 s, what would be the final velocity of the object? 3 - A stone of 1 kg is thrown with a velocity of 20 m s
^{–1}across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice? 3 - An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 m s
^{–2 }? 3 - From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m s
^{–1}. Calculate the initial recoil velocity of the rifle 3