Friction

Traveling at a speed of 15.5 m/s, the driver of an automobile suddenly locks the wheels by slamming on the brakes. The coefficient of kinetic friction between the tires and the road is 0.750. What is the speed of the automobile after 1.10 s have elapsed? Ignore the effects of air resistance.

A person is trying to judge whether a picture (mass = 1.30 kg) is properly positioned by temporarily pressing it against a wall. The pressing force is perpendicular to the wall. The coefficient of static friction between the picture and the wall is 0.585. What is the minimum amount of pressing force that must be used?

Statement1: It takes much longer time and covers more distance to stop a moving ship in water than a moving car with same speed on the road.

Statement2: The friction on water surface is much less than the solid surface.

• Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1.

• Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1.

• Statement 1 is true but statement 2 is false.

• Statement 1 is false but statement 2 is true.

THE MEASUREMENT OF THE AMOUNT OF FRICTION A SURFACE WILL GENERATE IS CALLED THE '_________ OF FRICTION'.

• CALIBRATION

• COEFFICIENT

• SMOOTHNESS

• DESCRIPTION

• FACT

is present as a body slides over another surface.

• Sliding Friction

• Starting Friction

• Friction

• Rolling Friction

What is the Newton's 2nd Law of Motion?

• equal and opposite reations

• law of inertia

• law of gravity

• f = ma

• A

• B

• C

• D

is present when a body, which has been at rest, just begins to move under the application of a force.

• Sliding Friction

• Starting Friction

• Friction

• Rolling Friction

AIR RESISTANCE ON A FLYING AIRPLANE IS AN EXAMPLE OF WHAT TYPE OF FRICTION?

• DRY FRICTION

• ROLLING FRICTION

• FLUID FRICTION

• STATIC FRICTION

• NONE OF THE ABOVE

Which would NOT be a way of reducing friction?

• making the surfaces smoother
• using lubricants such as waxes, oils, or grease
• changing from sliding friction to rolling friction using ball bearings
• Using kitty litter on snow and ice to help your car gain traction