Unit Test class - 11

The acceleration of a particle starting from rest varies with time t according to the equation: a = kt + c where k and c are constants. At time t, the velocity of the particle is

• kt + ct

• ½(kt²) + ct

• ½(kt²) + 1/2(ct²)

• kt² + ct

If a particle travels a linear distance at speed V₁ and comes back along the same track at speed V₂:

• Its average speed is arithmetic mean (V₁ + V₂)/2

• Its average speed is $\sqrt{V_1V_2}$

• Its average speed is $\frac{2V_1V2}{V_1\ +\ V_2}$

• None of these

The displacement s of a point moving in a straight line is given by, S = 8t² + 3t – 5, ‘S’ being in cm and 't' in s. The acceleration of the particle is:

• $5ms^{-2}$

• $2ms^{-2}$

• $3ms^{-2}$

• $8ms^{-2}$

Find the incorrect statement out of the following:

• If acceleration = 0, motion is uniform

• If acceleration = constant, acceleration is uniform but motion not uniform

• If acceleration $\ne$ constant, both acceleration and motion are not uniform

• Acceleration = constant both acceleration and motion are uniform

The velocity of a body depends on time according to the equation V = 20 + 0.1t². The body is undergoing:

• Uniform acceleration

• Uniform retardation

• Non–uniform acceleration

• Zero acceleration

A body starting from rest covers a distance of 9 m in the fifth second. The acceleration of the body is:

• 2 m/s²

• 0.2 m/s²

• 1.8 m/s²

• 4 m/s²

Fermi is the unit of ....

• Electric flux

• Time

• Mass

• Lenght

If the dimensions of a physical quantity are given by [ $M^aL^bT^c$   ], then the physical quantity will be

• Force, if a = -1, b = 0, c = -2 

• Velocity, if a = 1, b = 0, c = 1

• acceleration, if a = 1, b = 1, c = -2

• pressure, if a = 1, b = -1, c = -2 

The length, breadth and height of a rectangular block of The pressure on a square plate is measured by measuring the force on the plate and the length of the sides of the plate. If the maximum error in the measurement of force and length are respectively 4% and 2%, The maximum error in the measurement of pressure is  

• 1%

• 2%

• 6%

• 8%

Which of the following set have different dimensions?

• Pressure, Young’s modulus, stress

• e.m.f, potential difference, electric potential

• Heat, work done, energy

• dipole moment, electric flux, electric field