Question

How much work is done when a 165 g tomato is lifted 13.4 m? The tomato is dropped. What is the velocity, v, of the tomato when it hits the ground? Assume 88.1 % of the work done in Part A is transferred to kinetic energy, E, by the time the tomato hits the ground.

Answer 1

How much work is done when a 165 g tomato is lifted 13.4 m? The tomato is dropped. What is the velocity, v, of the tomato when it hits the ground? Assume 88.1 % of the work done in Part A is transferred to kinetic energy, E, by the time the tomato hits the ground.

Solution:

Work = Force * Displacement

Force is weight. In our case tomato was lifted therefore to calculate force we must multiply it with gravitational constant. We also need to convert weight to kg.

           = 0.165kg * 9.8m/s^2* 13.4 m = 21.66 J

For second part, we assume that 88.1% of energy is transferred to kinetic energy.

That is 21.66 * 0.81 = 17.54 J

KE = 1/2mv^2

17.54 = ½ * 0.165 * v^2

2*17.54 = 0.165 * v^2

212.60 = v^2

V = sqrt(212.60) = 14.58 m/s

The velocity when tomato hit the ground is 14.58 m/s.