速率、加速度與運動方程式：练习题

Which of the following physical quantities is a vector quantity?

A car of mass \(1200\text{ kg}\) is travelling at a constant velocity. A resultant force of \(3000\text{ N}\) is applied to the car in the direction of its motion. Calculate the acceleration of the car.

A rocket of mass \(2000\text{ kg}\) is launched vertically. Its engines produce a constant upward thrust of \(25000\text{ N}\). Calculate the acceleration of the rocket at the moment of launch.
(Assume \(g = 10\text{ N/kg}\))

A student observes a car moving along a straight road. The car travels a distance of \(450\text{ m}\) in a time of \(30\text{ s}\). Calculate the average speed of the car.

An object is moving in a circular path at a constant speed. Which of the following statements is incorrect regarding its motion?

A car travels a distance of 1500 metres in 60 seconds. Calculate the average speed of the car.

A runner accelerates from rest to a velocity of \(6\text{ m/s}\) in a time of \(3\text{ seconds}\). Calculate the acceleration of the runner.

A resultant force of \(20\text{ N}\) acts on an object of mass \(4\text{ kg}\) for \(5\text{ seconds}\). Calculate the change in momentum of the object.

A delivery van travels along a straight road. It travels at a constant speed of \(12\text{ m/s}\) for \(20\text{ seconds}\) and then accelerates uniformly to a speed of \(18\text{ m/s}\) over the next \(10\text{ seconds}\).

A ball is thrown vertically upwards with an initial velocity of \(15\text{ m/s}\). Ignore air resistance. Use \(g = 10\text{ m/s}^2\).