力及其相互作用：練習題

The weight of an object on Earth is the force acting on it due to gravity. What is the weight of a suitcase with a mass of \( 12 \text{ kg} \) on Earth? (Take \( g = 9.8 \text{ N/kg} \))

Calculate the work done when a force of \( 200 \text{ N} \) moves a crate a distance of \( 4 \text{ m} \) in the direction of the force.

(HT only) A spring is compressed by \( 0.1 \text{ m} \). If the spring constant is \( 400 \text{ N/m} \), calculate the elastic potential energy stored in the spring.

A scalar quantity is different from a vector quantity because it only has magnitude. Which of the following is a scalar quantity?

A car is travelling at a constant speed along a straight, level road. According to Newton's First Law, which statement about the forces acting on the car is true?

State whether weight is a scalar or a vector quantity and explain why by referring to its properties.