Why are the soles of the shoes treaded?

• To decrease friction
  
  

• To increase friction
  
  

• To increase life of the shoes
  
  

• To give the shoes more protection

The change in seasons on the earth occurs because

• the axis of rotation of the earth is tilted with respect to the plane of its orbit
  
  

• the distance between the earth and the sun is not constant
  
  

• the axis of rotation of the earth is parallel to the plane of its orbit
  
  

• the axis of rotation of the earth is perpendicular to the plane of its orbit

If the frequency of a simple pendulum is 2 Hz, how many oscillations will it complete in 16s?

• 16

• 64

• 32
  
  

• 8

Which of the following is/are example(s)of non-contact force?

• Muscular force
  
  

• Gravitation force
  
  

• Magnetic force
  
  

• Both (A) and (B)

Which of the following properties of water can be used to explain the spherical shape of rain droplets?

• Surface tension
  
  

• Critical phenomenon
  
  

• Viscosity
  
  

• Pressure.

The speed of sound is maximum in

• water
  
  

• vacuum
  
  

• air
  
  

• steel

Which one of the following is a renewable resource of energy?

• Petroleum
  
  

• Groundwater
  
  

• Natural gas
  
  

• Coal

Which physical unit is obtained by the ratio of momentum and velocity of matter?

• Acceleration
  
  

• Mass
  
  

• Velocity
  
  

• Force

9.

The SI unit of heat is

• joule
  
  

• erg
  
  

• calorie
  
  

• watt

If P, F and A represent pressure, force and area respectively, then

• $P$=$\frac{\mathbf{F}}{\mathbf{A}}$

• $P=\frac{F}{A}$

• $\mathbf{P}=\frac{\mathbf{F}}{A}$

• $P=\frac{\mathbf{F}}{A}$