1. Calculate the watts of power expended when a force of 1 N moves a book 2 m in a time interval of 1 s. 2. Show that 140 W of power is expended when a 20-N force pushes a cart 3.5 m in a time of 0.5...

1. Calculate the watts of power expended when a force of 1 N moves a book 2 m in a time interval of 1 s.

2. Show that 140 W of power is expended when a 20-N force pushes a cart 3.5 m in a time of 0.5 s.

Gravitational potential energy = weight
 height, PE = mgh

3. How many joules of potential energy does a 1.5-kg book gain when it is elevated 2 m? When it is elevated 4 m? (Let g = 10 N/kg.)