Two froghoppers sitting on the ground aim at the same leaf, located 35 cm above the ground. Froghopper A jumps straight up while froghopper B jumps at a takeoff angle of 58° above the horizontal.

Which froghopper experiences the greatest change in kinetic energy from the start of the jump to when it reaches the leaf?

Answer: A

Explanation: We can use the concept of conservation energy which implies that the kinetic energy of the froghoppers equals it potential energy from the ground level.

Where potential energy = mgh

Where m = mass of the object, g = acceleration due gravity and h = height from ground level.

The value of potential energy will reduce when the height is inclined at an angle.

Let us assume equal mass for both froghoppers, say m, g = 10 m/s^2 and a value of h.

For the first froghopper, potential energy = m*9.8*h = 9.8 mh

For the second froghopper, potential energy = m*9.8*hsin58 (hsin58 is the vertical componet of height h inclined at angle 58),

potential energy = 8.3109 mh

As we can see, froghopper A has more potential energy than froghoppers B which implies that A has more kinetic energy than B