Which of the following is true about friction?

• Friction is not present in a smooth surface

• Friction slows down a moving object

• Smooth surface has more friction

• Objects move slowly on a rough surface

You rolled a marble on a very smooth surface. Without friction, what might happen to the marble?

•     It will stop immediately.

• It will maintain its speed and suddenly stop.

• It will move either to the right or left side and stop

•    It will continuously move until it strikes another object.

You have noticed that your door hinges create a squeaky sound and hard to open. After applying some lubricants on it, the squeaky sound disappeared and made it easy to be opened. How do lubricants affect friction?

•   Lubricants decrease friction and causes objects to move faster.

•   Lubricants has no effect on the movement of objects.

• Lubricants increase friction and causes objects to move faster.

• Lubricants slows down the movement of objects.

When you rolled your rubber ball on the grassy surface of the ground, it suddenly stops. How does friction affect the motion of the ball?

•   Friction affects the ability of the ball to take more rolling.

• Friction decreases the time of the ball to take farther distance.

  
  

• Direction of the ball to change its direction.

• Friction slows down the rolling of the ball and prevents the ball to move farther.

A boy who weighs 35 kilos jumps higher than another boy who weighs 50 kilograms. How does gravity affect the jumps?

• The heavier the object, the lesser gravity.

• The lighter the object, the lesser gravity.

• The stronger the gravity, the higher the jump.

• Gravity does not affect how high one can jump.

A car travels faster when going down than in going up? Why?

•   Gravity pulls the car.

• It is being pushed by the wind.

• It is being pulled by the weight of the car.

• It is moving against gravity.

A metal ball and a sheet of paper are dropped at the same time from the same height. What will happen when there is no air resistance?

•     The metal ball will land first.

• The metal ball will float slowly through the air.

   

• The metal ball and the paper will land at the same time.

• The paper will land earlier than the metal ball.

A car and a truck are climbing the slope of a hill. Which of the two vehicles will reach the top faster? Why?

• The car because it has smaller engine than the truck.

• The truck because it has bigger fuel tank than the car.

• The car because it is smaller and lighter than the truck and has lesser gravity.

• The truck because it is bigger and heavier than the car and has more gravity.

Your kite flies up in the air and when the wind stops blowing, it goes down. Why?

• Gravity pulls the kite down.

• The wind pulls the kite down to the ground

•   There is no air around, so the kite goes down.

• The force of gravity flies the kite up and moves it down.

If a sheet of paper is burned, what energy is given off which we see as a flame?

• Sound and smell energy
• Heat and light energy
• Kinetic and potential energy
• Chemical and electrical energy