7. You are likely to slide on a shiny floor? Why?
A. because friction is more on smooth surface
B. because friction is less on smooth surface
C. because there is no friction on smooth surface
D. because friction cannot hold you on smooth surface
8. Is friction important to cars? Why?
A. Yes, because friction causes the cars to stop.
B. Yes, because friction causes the cars to move.
C. No, because friction can't slow down cars.
D. No, because friction has no effect on cars.
9. Why do tires have hollows and bumps?
A. in order to slide on the surfaces.
B. In order to drag over the surfaces.
C. In order to hold on to different surfaces.
D. In order to move fast.
10. A ball will roll faster on the floor than on the grass? Why?
.
A. because there is less friction on the floor than on the grass
B. because there is more friction on the floor than on the grass
C. because there is less friction on the grass than on the floor
D. because there is no friction on the grass and floor
Answers
Answer:
A
Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. Heavier objects also have more friction because they press together with greater force. Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy
B
Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. Heavier objects also have more friction because they press together with greater force. Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.
C
Friction is a force that opposes motion between any surfaces that are touching. Friction occurs because no surface is perfectly smooth. ... Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.
D
Friction affects the relative motion between two bodies in contact. Without friction, objects cannot move from a stationary position or stop when in motion. Suppose you are walking on the road and encounter a smooth surface. You will fall because there will be no friction to hold your feet firmly on the surface.
Q8
A
The force of friction opposes the motion of an object, causing moving objects to lose energy and slow down. When objects move through a fluid, such as air or water, the fluid exerts a frictional force on the moving object.
B
Friction does help in movement of a wheel aka rolling motion. See the image, the point touching the surface actually stays at rest which causes the rest of the wheel to move forward. This is caused due to friction.
C
So, even though friction is often thought of as the force that opposes the motion of an object, the motion of a car would not be possible without friction! Friction may slow the car down as it moves along the road, but it also is the force that enables the car to move forward at all.
D
To reduce friction, oil is added to the engine. The oil coats the surfaces of the moving parts and makes them slippery. ... Without friction, you would not be able to walk, the wheels on a vehicle would have no grip on a road surfacing and the vehicle would not be able to move forward.
Q9
A
Frictional force always acts always opposite to the direction of motion. Force of friction will be always parallel to the surfaces in contact. You spill a bucket of soapy water on a marble floor accidently. Would it make it easier or more difficult for you to walk on the floor?
B
The total aerodynamic force is equal to the pressure times the surface area around the body. Drag is the component of this force along the flight direction. Like the other aerodynamic force, lift, the drag is directly proportional to the area of the object. Doubling the area doubles the drag.
C
to demand that someone act on a promise or agreement: They're holding him to the exact terms of the contract.
D
It is because the rough surface is having more friction that the smooth surface. A ball, rolls faster in a smooth surface because it is having less or no friction at all to stop it. In the other case, there is friction to stop the ball
Q10
A
There is friction between the grass and the ball. ... Friction is the force that one surface exerts on another with the two surfaces rubbing together. The strength of the force of friction depends on the following two factors: The types of surfaces that are touching.
B
sandy floor. because sand is of coarse in texture. the rougher the texture the more friction. a wet floor has less friction because water sticks to the surface and somewhat coats the area leaving it with less friction.
C
There is friction between the grass and the ball. ... Friction is the force that one surface exerts on another with the two surfaces rubbing together. The strength of the force of friction depends on the following two factors: The types of surfaces that are touching.
D
It opposes motion, meaning if something is sliding on the floor, friction is the force that makes it eventually come to a stop. In a world without friction, the object would continue to slide forever, if not acted on by another force.
Explanation: