DPP – 9S81
FIRST LAW OF MOTION, INERTIA & SECOND LAW OF MOTION
1. State the law of Inertia, Explain the type of Inertia.
2. 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. Which would require a greater force –
accelerating a 2 kg mass at 5 m s–2 or a 4 kg mass at 2 m s-2 ?
4. A motorcar is moving with a velocity of 108 km/h and it takes 4 s to stop after the brakes are applied. Calculate the force exerted by the brakes on the motorcar if its mass along with the passengers is 1000 kg.
5. The velocity-time graph of a ball of mass 20 g moving along a straight line on a long table is given in figure given below.
6. How much force does the table exert on the ball to bring it to rest?
7. A force of 5 N gives a mass m1 , an acceleration of 10 m s–2 and a mass m2 , an acceleration of 20 m s-2 . What acceleration would it give if both the masses were tied together?
8. When a carpet is beaten with a stick, dust comes out of it, Explain.
9. Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?
10.Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.81