Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

Advertisement

111.

A rocket of mass 100 kg burns 0.1 kg of fuel per sec. If velocity of exhaust gas is 1 km/sec, then it lifts with an acceleration of

1000 ms

^{-2}100 ms

^{-2}10 ms

^{-2}1 ms

^{-2}

Advertisement

A bullet emerge from a barrel of length 1.2 m with a speed of 640 ms^{-1} . Assuming constant acceleration, the approximate time that it spends in the barrel after the gun is fired is

4 ms

40 ms

400 μs

1 s

A.

4 ms

Given that, s = 1.2 m and v = 640 ms^{-1}, a = ? ; u = 0 ; t = ?

We have the third equation of motion

2as = v^{2} − u^{2}

2a × 1.2 = 640 × 640

or $\mathrm{a}=\frac{8\times 64\times {10}^{3}}{3}$

and by first equation of motion

v = u + at

or t = $\frac{\mathrm{v}}{\mathrm{a}}$ = $\frac{15}{4}$ × 10^{-3}

= 3.75 × 10^{-3}

s = 4 ms

Advertisement

113.

The acceleration a (in ms^{-2} ) of a body, starting from rest varies with time t (in s) following the equation a = 3 t + 4. The velocity of the body at time t = 2 s will be

10 ms

^{-1}18 ms

^{-1}14 ms

^{-1}26 ms

^{-1}

114.

Figure below shows the distance-time graph of the motion of a car. It follows from the graph that the car is

at rest

in uniform motion

in non-uniform acceleration

uniformly accelerated

Advertisement

115.

A shell of mass m is at rest initially. It explodes into three fragments having masses in the ratio 2 : 2 : 1. The fragments having equal masses fly off along mutually perpendicular direction with speed v. What will be the speed of the third (lighter) fragment ?

116.

If a person can throw a stone to maximum height of h metre vertically, then the maximum distance through which it can be thrown horizontally by the same person is

$\frac{\mathrm{h}}{2}$

h

2h

3h

117.

A box is moved along a straight line by a machine delivering constant power. The distance moved by the body in time t is proportional to

t

^{1/2}t

^{3/4}t

^{3/2}t

^{2}

118.

A particle is moving with a constant speed v in a circle. What is the magnitude of average velocity after half rotation ?

2v

$2\frac{\mathrm{v}}{\mathrm{\pi}}$

$\frac{\mathrm{v}}{2}$

$\frac{\mathrm{v}}{2\mathrm{\pi}}$

Advertisement

119.

A box of mass 2 kg is placed on the roof of a car. The box would remain stationary until the car attains a maximum acceleration. Coefficient of static friction between the box and the roof of the car is 0.2 and g = 10 ms^{-2}. This maximum acceleration of the car, for the box to remain stationary, is

8 ms

^{-2}6 ms

^{-2}4 ms

^{-2}2 ms

^{-2}

120.

A particle is travelling along a straight line OX. The distance x (in metre) of the particle from O at a time t is given by x = 37 + 27t − t^{3}, where t is time in seconds. The distance of the particle from O when it comes to rest is

81 m

91 m

101 m

111 m

Advertisement