A. Force and acceleration
B. Force and area
C. Force and instantaneous velocity
D. Force and displacement
Correct Answer: D. Force and displacement
Work done is defined as the dot product of Force vector and displacement vector. W = F.s Work done is a scalar quantity. Note: Instantaneous power is defined as the dot product of the Force vector and instantaneous velocity.
A. in the same direction as the rocket
B. in the opposite direction of the rocket
C. at 90° to the direction of the rocket
D. None of the above
Correct Answer: B. in the opposite direction of the rocket
The thrust on the rocket is in the opposite direction of the rocket. The thrust is the force with which the rocket moves upwards. F = -u (dm/dt).
A. 1
B. 0
C. -1
D. 1/2
Correct Answer: B. 0
When two vectors are perpendicular to each other, then θ = 90° and Cos 90° = 0 . Therefore, A.B = A x B x Cos θ = A x B x Cos 90° = 0.
A. equal to the actual weight
B. greater than the actual weight
C. less than the actual weight
D. Zero
Correct Answer: C. less than the actual weight
The apparent weight of the person becomes less than the actual weight when the elevator is accelerating downwards. The apparent weight of the person becomes more than the actual weight when the elevator is accelerating upwards.
A. equal to its maximum range
B. one half of its maximum range
C. one-fourth of its maximum range
D. twice of its maximum range
Correct Answer: C. one-fourth of its maximum range
The maximum height that can be attained by a projectile is equal to one-fourth of its maximum range.
A. it is minimum at the point of projection
B. it is minimum at the highest point
C. it is maximum at the highest point
D. it is minimum at the point of reaching the ground
Correct Answer: B. it is minimum at the highest point
The Kinetic energy of an object is maximum at the point of projection or at the point of reaching the ground. It is minimum at the highest point.
A. when vectors act in the same direction
B. when vectors act in the opposite direction
C. when vectors act at 90° to each other
D. None of the above
Correct Answer: A. when vectors act in the same direction
The magnitude of the resultant of two vectors is maximum when vectors act in the same direction. The magnitude of the resultant of two vectors is minimum when vectors act in opposite directions.
A. Entropy
B. Permittivity of free space
C. Latent heat
D. Gas constant
Correct Answer: C. Latent heat
Joule/kg is the S.I unit of Latent heat (L) = heat(Q)/mass(m) Latent heat is the heat required to convert a solid into a liquid or vapor, or a liquid into a vapor, without any change in temperature.
A. 10-12
B. 10-14
C. 10-15
D. 1-24
Correct Answer: C. 10-15
1 femto metre is equal to 10-15 metre. Some other metric prefixes are:
A. Celsius
B. Fahrenheit
C. Kelvin
D. Rankine
Correct Answer: C. Kelvin
Kelvin is the base unit of temperature (SI unit), having the unit symbol K. The Kelvin temperature scale has an absolute zero (0°K) below which temperatures do not exist.