the effect of a set of forces on an object

an object will remain at rest, or in motion in a straight line at constant speed, unless there is a resultant force acting on it

the rate of change of displacement of an object, measured in metres per second (m/s)

a change in the speed and/or direction of an object

Resultant forces and their effects

Combined science

In the Gravity in space unit, they will build on this knowledge to learn about centripetal forces, orbital motion, stellar evolution, red shift and the big bang.

In the Energy of moving objects unit, pupils learnt how to calculate the amount of energy of objects have because they are moving, stretched or in a gravitational field; and to calculate energy transfers using knowledge of energy conservation and dissipation.

Forces make things change

The diagram shows four forces acting on an object. What is the magnitude of the resultant force?

Which of the following is not caused by a resultant force acting on an object?

A stationary object remains stationary if there is no resultant force.

Every action has an equal and opposite reaction.

A moving object’s velocity stays the same if no resultant force acts.

When object A exerts a force on object B, B also exerts a force on A.

Which of the following statements are included in Newton’s First Law of motion?

There is a steady resultant force acting on the ship.

There is no resultant force acting on the ship.

The force pushing it forwards is equal to the force pushing it backwards.

The force pushing it forwards is greater than the force pushing it backwards.

A ship travels at a constant speed without changing direction. Which of the following statements are correct?

The person’s pushing force transfers to the thermal store.

There is a resultant force acting in the opposite direction to the motion.

Other forces cancel out the person’s pushing force.

A person pushes a stone across a frozen lake. After they let go, the stone slides across the ice, slowing and stopping before it reaches the other side of the lake. Why does the stone slow and stop?

Which of the following vans is decelerating?

How many newtons (N) are there in 2.5 MN?

When two or more forces act on an object, we can imagine a single force that has the same effect as this combination of forces. This single force is called the {{}} force.

A coin is dropped into a swimming pool. While the coin is falling downwards through the water, which of the following forces act on it?

There is a law of physics which states that forces come in equal and opposite pairs, which act between pairs of objects. What is the name of this law?

change in displacement divided by time taken

time taken to change velocity by one metre per second

Which of the following are correct definitions of acceleration?

A car increases speed as it travels in a straight line.

A car travels in a straight line at a steady speed.

A car turns a corner without changing speed.

Which of the following situations involve a change in velocity?

This lesson will soon be taken down.

Resultant forces and their effects

Lesson outcome