Rolling friction

Two factors that determine work are...

• Force

• Mass

• Velocity

• Distance

He found out the element Hydrogen which was "Inflammable air". Guess who he is?(Starting Letters Capital)

Which of the colors below represent Potassium Flame?

• 
• 
• 
• 

If we drop a steel sphere and a ping pong ball, the steel sphere will...

• hit the ground first because it has more mass
• hit the ground second because it takes longer to accelerate 
• hit the ground at the same time as the ping pong ball 

While measuring the lenght of a of a kerchief, the reading of the scale at one end is 2.0 cm and at the other end is 33.cm. What is it’s length ?

• 33.1 cm

• 30.1 cm

• 31.1 cm

• 29.1 cm

Observe the given picture. What do you conclude from this?

• The frictional force depends on the nature of the two surfaces in contact.

• Frictional force increases as mass increases.

• Rolling friction is less than sliding friction.

• Frictional force is muscular force.

There are two jars, one is filled with water and another is empty as shown in the figure. Two balls are released from the top. In which jar does the ball reach the bottom first?

• In jar filled with water

• In jar without water

• In both the jars at the same time

• Cannot be said because data is insufficient.

An object at rest will _______ if no outside forces are applied.

• Stay at rest
• Increase Velocity
• Decrease Mass

Planets do not twinkle because___________.

• they emit light of a constant intensity.

• their distance from the earth does not change with time

• they are very far away from the earth resulting in decrease in he intensity of light.

• they are nearer to earth and hence we receive a greater amount of light and therefore minor variations are not noticeable.

A ball rolling over the surface of a smooth playground stops after sometime.Why?

• Friction

• Gravitation

• Magnetism

• Mechanical