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Forces and Motion - Push and pull forces

Grade 3Cambridge (IGCSE)

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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A force is a push or a pull that acts upon an object as a result of its interaction with another object.

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Forces can make objects start moving, stop moving, change their speed, or change their direction.

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Forces can also change the shape of an object (e.g., stretching a rubber band or squeezing clay).

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A 'Push' is a force that moves an object away from you, while a 'Pull' is a force that moves an object toward you.

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Forces are measured using a device called a force meter (or Newton meter).

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The unit of measurement for force is the Newton, represented by the symbol NN.

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Friction is a contact force that occurs when two surfaces rub against each other, acting in the opposite direction to motion.

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Gravity is a non-contact force that pulls objects toward the center of the Earth.

📐Formulae

Total Force=Force1+Force2 (if in the same direction)\text{Total Force} = \text{Force}_1 + \text{Force}_2 \text{ (if in the same direction)}

Net Force=Forcepush−Forcepull (if in opposite directions)\text{Net Force} = \text{Force}_{push} - \text{Force}_{pull} \text{ (if in opposite directions)}

Unit of Force=N\text{Unit of Force} = N

💡Examples

Problem 1:

Sarah is opening a heavy drawer. She moves the handle toward her body. Is this a push or a pull force?

Solution:

It is a Pull force.

Explanation:

Since Sarah is moving the object toward herself, it is classified as a pull.

Problem 2:

A toy car is pushed with a force of 10N10 N to the right, but friction pushes back with 2N2 N to the left. What is the net force acting on the car?

Solution:

10N−2N=8N10 N - 2 N = 8 N

Explanation:

To find the net force when forces act in opposite directions, we subtract the smaller force from the larger force. The car moves with a force of 8N8 N to the right.

Problem 3:

Identify the forces: (A) Kicking a football, (B) Picking up a school bag from the floor.

Solution:

(A) Push, (B) Pull

Explanation:

Kicking involves moving the ball away from the foot (Push), while picking up a bag involves moving it toward the body/upward (Pull).