State what is meant by the mass of a body.

1. (a)State what is meant by the mass of a body.[1]
2. (b)(i)Two blocks travel directly towards each other along a horizontal, frictionless surface. The blocks collide, as illustrated in Fig. 3.1. 0.40 m s⁻¹ 0.25 m s⁻¹ 0.20 m s⁻¹ v block A block B mass 3M mass M before mass 3M mass M after Fig. 3.1 Block A has mass 3M and block B has mass M. Before the collision, block A moves to the right with speed 0.40ms⁻¹ and block B moves to the left with speed 0.25ms⁻¹. After the collision, block A moves to the right with speed 0.20 ms⁻¹ and block B moves to the right with speed v. (i) Use Newton's third law to explain why, during the collision, the change in momentum of block A is equal and opposite to the change in momentum of block B.[2]
3. (b)(ii)(ii) Determine speed v. V=[3]
4. (b)(iii)1.(iii) Calculate, for the blocks, 1. the relative speed of approach, relative speed of approach =[1]
5. (b)(iii)2.2. the relative speed of separation. relative speed of separation =[1]
6. (b)(iv)(iv) Use your answers in (b)(iii) to state and explain whether the collision is elastic or inelastic.[1]

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