1. The unit of linear acceleration is
a) kg-m
b) m/s
c) m/s2
d) rad/s2
Explanation: Linear acceleration is defined as the rate of change of linear velocity of a body with respect to the time.
i.e a = v/t and unit of velocity is m/s
so, unit of linear acceleration becomes m/s2
2. The angular velocity (in rad/s) of a body rotating at N r.p.m. is
a) π N/60
b) 2 π N/60
c) π N/120
d) π N/180
Explanation: Angular velocity is defined as the rate of change of angular displacement with respect to time. It is usually expressed by a Greek letter ω (omega).
Mathematically, angular velocity,
ω =dθ/dt
If a body is rotating at the rate of N r.p.m. (revolutions per minute), then its angular velocity,
ω = 2πΝ / 60 rad/s
3.The linear velocity of a body rotating at ω rad/s along a circular path of radius r is given by
a) ω.r
b) ω/r
c) ωs2.r
d) ωs2/r
Explanation: If the displacement is along a circular path, then the direction of linear velocity at any instant is along the tangent at that point. therefore, the linear velocity will be ω.r
4. When a particle moves along a straight path, then the particle has
a) tangential acceleration only
b) centripetal acceleration only
c) both tangential and centripetal acceleration
d) none of the mentioned
Explanation: The acceleration of a particle at any instant moving along a circular path in a direction tangential to that instant, is known as tangential component of acceleration or tangential acceleration.
5. When a particle moves with a uniform velocity along a circular path, then the particle has
a) tangential acceleration only
b) centripetal acceleration only
c) both tangential and centripetal acceleration
d) none of the mentioned
Explanation:The acceleration of a particle at any instant moving along a circular path in a direction normal to the tangent at that instant and directed towards the centre of the circular path is known as normal component of the acceleration or normal acceleration. It is also called radial or centripetal acceleration
6. When the motion of a body is confined to only one plane, the motion is said to be
a) plane motion
b) rectilinear motion
c) curvilinear Motion
d) none of the mentioned
Explanation: When the motion of a body is confined to only one plane, the motion is said to be plane motion. The plane motion may be either rectilinear or curvilinear.
7. _______________ is the simplest type of motion and is along a straight line path.
a) plane motion
b) rectilinear motion
c) curvilinear Motion
d) none of the mentioned
Explanation: Rectilinear Motion is the simplest type of motion and is along a straight line path. Such a motion is also known as translatory motion.
8. _________________ is the motion along a curved path.
a) plane motion
b) rectilinear motion
c) curvilinear Motion
d) none of the mentioned
Explanation: Curvilinear Motion is the motion along a curved path. Such a motion, when confined to one plane, is called plane curvilinear motion.
9. Displacement of a body is a ___________ quantity.
a) scalar
b) vector
c) scalar and vector
d) none of the mentioned
Explanation: The displacement of a body is a vector quantity, as it has both magnitude and direction. Linear displacement may, therefore, be represented graphically by a straight line.
10. A train covers 60 miles between 2 p.m. and 4 p.m. How fast was it going at 3 p.m.?
a) 60 mph
b) 30 mph
c) 40 mph
d) 50 mph
Explanation: The speed is traveled distance (60 miles) divided by traveled time (4pm – 2pm = 2hours):
60 miles/ 2 hours = 30 mph