Key concepts of physics：練習題

Which of the following is the correct multiplier for the SI prefix micro (\(\mu\))?

A car travels a distance of \(450\text{ metres}\) in \(30\text{ seconds}\). Calculate its average speed in \(\text{m/s}\).

An object is moving in a circular orbit at a constant speed. Which statement best describes the velocity and acceleration of the object?

Which of the following units is used for magnetic flux density?

A student is using the following equation to calculate the weight of an object:
\(W = m \times g\)
If an object has a mass of \(500\text{ g}\) and the gravitational field strength is \(10\text{ N/kg}\), what is the weight of the object?

State the SI unit for force.

The speed of a train increases from \(10\text{ m/s}\) to \(30\text{ m/s}\) over a distance of \(400\text{ metres}\).
(a) Calculate the acceleration of the train, assuming it is uniform.
(b) The train has a mass of \(2.5 \times 10^5\text{ kg}\). Calculate the resultant force required to produce this acceleration.
(c) Calculate the change in kinetic energy of the train during this acceleration. Write your answer in standard form.