Question

The mass of a minibus with the driver is 1500kg. Assume that the passengers have an average mass of 50 kg each .The minibus is moving at a speed of 30 m/s when he notices that the traffic lights ahead have turned red. He replied a force of 900N on the brake pedal.
1. Calculate the deceleration if the taxis empty, that is, there were no passengers .
2. How long will it take him to stop ?
3. How will the stopping distance change if the minibus is carrying 10 passengers?