Brittany stands at rest on a skateboard. The combined mass of Brittany and the skateboard is 62 kg. Dave tosses a 3.7-kg pumpkin to Brittany, and when she catches it, she and the skateboard begin to roll backward with a speed of 0.18 m/s.
What was the speed of the pumpkin?

3.196 m/s

Explanation:

Parameters given:

Mass of Brittany and the skateboard, M = 62 kg

Mass of pumpkin, m = 3.7 kg

Initial speed of Brittany and the skateboard, U = 0 m/s

Final velocity of Brittany, the skateboard and the pumpkin, V = v = 0.18 m/s

We can solve this problem by applying the principle of conservation of momentum.

It states that the total final momentum of a system is equal to the total initial momentum of the system.

M*U + m*u = M*V + m*v

Where u is the initial velocity of the pumpkin.

Since the final velocity of Brittany and the skateboard is equal to the final velocity of pumpkin:

M*U + m*u = (M + m) *v

Solving this to get u:

(62 * 0) + (3.7 * u) = (62 + 3.7) * 0.18

0 + 3.7u = 65.7 * 0.18

3.7u = 11.826

u = 11.826 / 3.7

u = 3.196 m/s

The initial velocity of the pumpkin was 3.196 m/s.

i believe the answer is a

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

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