How fast must a 2.5-g ping-pong ball move in order to have the same kinetic energy as a 145 g baseball moving at 38.0 m/s?

Kinetic energy = (1/2)*m*v^2.  So we have (1/2)*(145 g)*(37 m/s)^2 = (1/2)*(2.5 g)*(v^2).

Solve for v = 281.78 m/s {about 630 miles per hour}

Explanation:

164.87 J

Explanation:

From the question,

Work done (W) = mghcosθ Equation 1

Where m = mass of the box, h = height, g = acceleration due to gravity, θ = angle to the vertical

Given: m = 25 kg, h = 2.6 meters, θ = 75°.

Constant: g = 9.8 m/s²

Substitute these value into equation 1

W = 25×9.8×2.6×cos75°

W = 164.87 J.