Prelim PDHPE Core 2 CQ3 Revision

Match the following principles of motion with their correct definition

• Velocity

• The quantity of motion that a body possesses

• Acceleration

• Movement of the body in a straight line

• Speed

• The distance covered divided by the time taken to cover that distance

• Momentum

• The rate at which velocity changes

• Linear Motion

• The displacement of an object or person over time, including direction

Velocity and speed are similar, but ​different.

​ (a)   does not have a ​ (b)   attached to it and is the distance covered by the athlete in a specified time.

​ (c)   is essentially the change in an athletes or objects position over time.

For example, in a 100m race speed and velocity will be the ​ ​ (d)   . However, in a 400m race an athletes velocity will be ​ (e)   because the start and finish in the same place.​ ​

• Speed
• direction
• Velocity
• same
• zero

Which is the correct equation for calculating speed?

Which is the correct equation for calculating acceleration?

Which is the correct equation for calculating momentum?

Identify the principles of motion being described in each of the following examples:

​ A) In rugby union, players who have a greater mass will have greater ​ (a)   making it easier to break and lay tackles.

​ B) In snowboarding, athletes need to maintain ​ (b)   in order to travel at faster speeds.

​ C) In sprinting, athletes with great ​ (c)   are able to reach their top speed quicker.

​ D) In touch football, players with good ​ (d)   are more difficult to tackle.

​ E) In cricket, ​ (e)   is used to measure the path of a cricket ball as it takes into account both the horizontal and the vertical movement of the ball.

• momentum
• linear motion
• acceleration
• speed
• velocity

Match the following principles of balance and stability with their correct definition

• Line of Gravity

• This is an imaginary line that is drawn from the centre of gravity to the ground

• Centre of Gravity

• The region bounded by the body parts in contact with a surface that is applying a reactive force against the applied force of the body

• Base of Support

• The point at which all the weight is evenly distributed and about which the object is balanced

If an athlete has a low centre of gravity, they will be:

• More stable

• Less stable

Does an athletes centre of gravity always need to lie within the physical limits of the athlete or object?

• Yes

• No

Identify where the centre of gravity would be for the athlete in this image

Answer explanation

During high jump, diving or gymnastics events, the centre of gravity changes rapidly and lies outside the body of the athlete.