Answers to questions asked in class. Introduction to gravitational force, friction and magnetic force.

1. Chapter 10
(Part 2)
Forces and Pressure

2. Quiz Time
O When you throw a ball in the air, what will
happen to the motion of the ball?
O Ball will fall towards earth after reaching
a maximum height.
Why?

3. Gravity
O Gravity or gravitational force is the
force that attracts objects to the earth.
O Thus gravity causes objects to falls towards
the earth.

4. Quiz Time
O You gave a push to a toy car across your
bedroom.
O Describe the motion of the toy car.
O The toy car moves but will start to slow down
and stop after a while.
WHY?

5. Friction
O Friction between the ground and the wheel
of the toy car slows down the toy car making
it coming to a stop.
O Friction is a force acting in the
opposite direction to the direction of
motion of the object .

6. Friction
Useful Nuisance
Enables us to walk forward. Causes wear and tear in
machine or object.
Prevents us from slipping and Reduces efficiency of a
falling. machine or object.
Enables us to hold on to Produces heat instead of
object. useful work.