A crate on a motorized cart starts from rest and moves with a constant eastward acceleration of a = 2.80 m/s2. A worker assists the cart by pushing on the crate with a force that is east-ward and has magnitude that depends on time according to F(t) = (5.40 N/s)t. What is the instantaneous power supplied by this force at t = 5.00 s?

Solution 48E Introduction We have to calculate the instantaneous power of the cart. The acceleration and initial velocity of the cart is given, hence we will be able to calculate the velocity at the given time. We will also calculate the force at the particular time from the given relationship of force with time. Hnce, from calculated velocity and time we can calculate the instantaneous power. Step 1 The instantaneous power is given by Step 2 The acceleration of the cart is a = 2.80 m/s , and the cart is starting from rest, hence the velocity after time t = 5 s, is