Question

Suppose you throw a rock nearly straight up at a coconut in a palm tree, and the rock just misses the coconut on the way up but hits the coconut on the way down. Neglecting air resistance and the slight horizontal variation in motion to account for the hit and miss of the coconut, how does the speed of the rock when it hits the coconut on the way down compare with what it would have been if it had hit the coconut on the way up? Is it more likely to dislodge the coconut on the way up or down? Explain.

a) The speed is less; more likely on the way up
b) The speed is less; more likely on the way down
c) The speed is the same; equally likely on both ways
d) The speed is greater; more likely on the way down

Answer 1

The speed of the rock when it hits the coconut on the way down is the same as when it would have hit the coconut on the way up, making it equally likely to dislodge the coconut on either trajectory.

Step-by-step explanation:

In this scenario, neglecting air resistance, the speed of the rock when it hits the coconut on the way down would be the same as what it would have been if it had hit the coconut on the way up.

When a projectile is thrown straight up and neglecting air resistance, it reaches the same speed on its way down as it did on its way up.

Therefore, it is equally likely to dislodge the coconut on the way up or down.