Question

Two blocks of clay, one of mass 1.00 kg and one of mass 3.00 kg, undergo a completely inelastic collision. Before the collision one of the blocks is at rest and the other block is moving with kinetic energy 32.0 J. If the 3.00 kg block is initially at rest and the 1.00 kg block is moving, what is the initial speed of the 1.00 kg block?

Answer 1

Answer:

The initial speed of the 1kg block is 8 m/s.

Explanation:

The question simply asks for the initial speed of the 1.00 kg block.

The initial kinetic energy of the 1kg block is = 32 Joules

Using this kinetic energy, and the equation below, we can find the speed of the 1kg block:

Kinetic Energy = $\frac{1}{2}m*v^2$

$32=\frac{1}{2}(1)*v^2$

$v = \sqrt{64}$

v = 8 m/s

The initial speed of the 1kg block is 8 m/s.

Answer 2

Answer:

Va1 = 8.0m/s

Explanation:

Let Va1 = the speed of the block1

Given the masses of the blocks

Ma = 1.0kg and Mb = 3.0kg

Kinetic energies of the blocks

Ka1= 32J and Kb1 = 0J

Ka1 = 1/2 × Ma × Va1²

32 = 1/2 × 1.0 × Va1²

Va1² = 2×32 =64

Va1² = √64 = 8.0m/s

In this problem we were given the kinetic energy of one of the blocks and also the masses of the blocks. So all we need to do is to use the formula for calculating the kinetic energy to relate ka1 to the mass Ma as done above.