Mechanics 1

A particle with mass 4kg is moving to the right at 2m/s. Another particle with mass 2kg is moving to the left at 2.5m/s. What is the total momentum in the system?

A particle, yes, another one, is thrown vertically upwards at a speed of u m s−1. It lands 3 seconds later. Ignoring air resistance, what is the value of u?

At time t=0, a particle of mass 0.5kg has a velocity of 2i−3j m s−1. After a constant force has been applied for five seconds, its velocity is −6i+3j m s−1. What is the magnitude of the force?

A particle of mass 4 kg lies on a smooth plane inclined at 20º to the horizontal. A horizontal force of 20 N is applied to the particle. What is the acceleration of the particle?