# ocr-21-c-science-b-paper-7

## Force on a Spring

When a force acts on a spring it is stretched or compressed, its length will changes by an amount e from its original length.

## Demo

In this tutorial you will learn how to calculate the **force** on a spring given its **extension** and** spring constant**.

**Note-**Some mobile devices may require you to tap full screen during playback to view video content.

The equation for this calculation is written like this:

$F = { \text k \; \text x \; \text e}$

## Chilled practice question

Copy out the question and attempt to calculate the answer before watching the solution. Write down the equation and show all of your working, remember to add the units to your answer, this routine will guarantee you maximum marks in an exam. Mark your solution and correct if needed.

A spring is stretched 0.25 **m**, it has a **spring constant** of 20 **N/m**, calculate the force on the spring.

## Frozen practice question

Copy out the question and attempt to calculate the answer before watching the solution. Write down the equation and show all of your working, remember to add the units to your answer, this routine will guarantee you maximum marks in an exam. Mark your solution and correct if needed..

A **force** of 10 **N** is applied to a spring and it extends by 20 **cm**, calculate its **spring constant**.

## Science in context

When a spring is stretched or compressed, its length will changes by an amount x from its original length, **force** **F = k**e. The **force** the spring exerts is its restoring **force**, it acts to restore the spring to its original length.

## Millie’s Master Methods

## The Fridge Physics Store

## Kinetic Energy

In physics, the ** kinetic energy (KE)** of an object is the

*that it has due to its motion. It is*

**energy***defined*as the work needed for an object of a known

**mass**to

**accelerate**to a given velocity.

## What is Kinetic energy?

In physics, the * kinetic energy* (KE) of an object is the

*that it has due to its motion. It is*

**energy***defined*as the work needed for an object of a known

**mass**to

**accelerate**to a given velocity.

## Kinetic energy equation

To calculate **Kinetic energy** we write the equation like this.

$E_k = { 1 \over2} mv {^2}$

## Kinetic energy demo

In this tutorial you will learn how to calculate the **energy** stored in a moving object.

## Chilled practice question

Copy out the question and attempt to calculate the answer before watching the solution. Write down the equation and show all of your working, remember to add the units to your answer, this routine will guarantee you maximum marks in an exam. Mark your solution and correct if needed.

Calculate the **Kinetic energy store** in a car with a **mass** of 850 **Kg** moving at a **velocity** of 3.5 **m/s**.

## Frozen practice question

Copy out the question and attempt to calculate the answer before watching the solution. Write down the equation and show all of your working, remember to add the units to your answer, this routine will guarantee you maximum marks in an exam. Mark your solution and correct if needed.

A meteorite has 8000 **J** of **Kinetic energy**, calculate its **mass** if it has a **velocity** of 20 **m/s**

## Science in context

Anything that is moving has energy in its** kinetic energy store**.