A shopper pushes a shopping trolley along a straight, level floor.
The mass of the trolley is 25 kg.
The shopper pushes the trolley forwards with a force of 40 N. The frictional force on the trolley is 15 N.
Calculate the acceleration of the trolley.
The trolley starts from rest and accelerates for 3.0 s.
Calculate the velocity of the trolley after 3.0 s.
Use the equation
acceleration=change in velocitytime taken\text{acceleration} = \dfrac{\text{change in velocity}}{\text{time taken}}acceleration=time takenchange in velocity
The shopper puts 15 kg of shopping into the trolley. She still pushes with a force of 40 N. The frictional force increases to 20 N.
Calculate the new acceleration of the trolley.
Explain why the acceleration in (c) is smaller than the acceleration in (a).