Newton's 2nd Law

Newton's 2nd Law

Objectives

• Know that forces affect the motion of an object.

• Be able to compare the rates of acceleration of objects, given information about the mass of the objects and the forces acting.

• Be able to use the equation F = m × a to solve numerical problems involving force, mass and acceleration.

Task 1

Listen as your teacher explains Newton's first two "Laws of Motion" and shows you a few demonstrations.

Now watch this video clip which should also help to explain.

Task 2

Write the title "Newton's Laws of Motion" in your exercise book, and copy the two laws given below:

Newton's First Law (basically) says:

if the forces on an object are balanced (or zero)

the object will either remain stationary or continue moving at a constant speed.

Newton's Second Law (basically) says:

if the forces on an object are unbalanced

the object will either accelerate (speed up) or slow down

and bigger forces produce bigger accelerations

Task 3

Stick this sheet into your exercise book. Look at each of the scenarios and use Newton's 2nd law to decide which object will accelerate at the greatest / lowest rate.

Task 4

It is useful to express the second law as a formula. Write the formula and equation triangle below in your exercise book.

F = m × a

F = Force

m = mass

a = acceleration

And it can also be written as an equation triangle:

Note: the formula is given in the examination, but the equation triangle is not given. If you find it easier to use the equation triangle then it is up to you to remember it!

Task 5

Your teacher will go through two example calculations with you. Pay attention and then copy the examples into your exercise book, laying out the calculation methodically as your teacher showed you.

Homework

Complete this sheet of calculations. Show full working for all calculations and remember to give units with your answers.