Module 3 - Section 1 - Projectile Motion

Question 1

Why do projectiles follow a curved path ?

Answer 1

This is because the horizontal velocity remains constant, while the vehicle component is affected by the acceleration due to gravity ‘g’

Question 2

Whats very important to do in projectile questions ?

Answer 2

You have to treat the horizontal and vertical components independently

Question 3

Whats the method to figure out projectiles that are on an angle ?

Answer 3

1) Resolve the initial velocity into horizontal and vertical components

2) Use the vertical component to work out how long its in the air and/or how high it goes

3) Use the horizontal component to work out how far it goes while its in the air

Question 4

How do you convert rads ( radians ) to degrees
And degrees to rads ?

Answer 4

To convert from rads to degrees you need to times by 180/pie

To convert degrees to rads you times by pie/180

Question 5

How will a displacement time graph look like when there is acceleration ?

And what will happen if the object is accelerating at a constant ( uniform rate ) ?

Answer 5

A displacement time graph when there is an accelerating object will always produce a curve

And if the object is accelerating at a uniform rate then the rate of change of the gradient will be constant therefore there will be a new gradient anywhere from the line you pick

Question 6

How do you plot a displacement time graph if you just have the time and velocity ?

For example:
Plot a displacement time graph for a lion who accelerates constantly from rest at 2ms*-2 for 5 secs

Answer 6

First you have to draw a table of results so time and displacement - we have time so write 0-5 in a column

Then we have to figure out displacement:

We know that a=2ms-2 and u=0ms-1
So put these into the equation s=ut+1/2 at*2

S=0xt + 1/2 x 2t2
S=t2