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Kinematics-2D

384 Questions Start Objective Test
All Exams Allen Objective Errorless
Q376 Errorless Self Evaluation Test MCQ
A particle is moving on a circular path of radius r with uniform velocity v. The change in velocity when the particle moves from P to Q is ( $\angle POQ = 40^{\circ}$ )
A.
$$<br /> 2 \nu \cos 4 0 ^ {\circ}<br /> $$
B.
$$<br /> 2 v \sin 4 0 ^ {\circ}<br /> $$
C.
$$<br /> 2 \upsilon \sin 2 0 ^ {\circ}<br /> $$
D.
$$<br /> 2 \nu \cos 2 0 ^ {\circ}<br /> $$
Q377 Errorless Self Evaluation Test MCQ
A particle does uniform circular motion in a horizontal plane. The radius of the circle is 20 cm. The centripetal force acting on the particle is 10 N. It's kinetic energy is
A.
0.1 J
B.
0.2 J
C.
2.0 J
D.
1.0 J
Q378 Errorless Self Evaluation Test MCQ
A particle moves with constant angular velocity in circular path of certain radius and is acted upon by a certain centripetal force $F$ . If the angular velocity is doubled, keeping radius the same, the new force will be
A.
2F
B.
$F^2$
C.
4F
D.
$F / 2$
Q379 Errorless Self Evaluation Test MCQ
A body of mass m kg is rotating in a vertical circle at the end of a string of length r metre. The difference in the kinetic energy at the top and the bottom of the circle is
A.
$\frac{mg}{r}$
B.
$\frac{2mg}{r}$
C.
2mgr
D.
mgr
Q380 Errorless Self Evaluation Test MCQ
A car is travelling with linear velocity v on a circular road of radius r. If it is increasing its speed at the rate of 'a' $m/s^2$ , then the resultant acceleration will be
A.
$\sqrt{\left\{\frac{v^{2}}{r^{2}}-a^{2}\right\}}$
B.
$\sqrt{\left\{\frac{v^{4}}{r^{2}}+a^{2}\right\}}$
C.
$\sqrt{\left\{\frac{v^{4}}{r^{2}}-a^{2}\right\}}$
D.
$\sqrt{\left\{\frac{v^{2}}{r^{2}}+a^{2}\right\}}$
Q381 Errorless Self Evaluation Test MCQ
A ball of mass 0.1 kg is suspended by a string. It is displaced through an angle of $60^{\circ}$ and left. When the ball passes through the mean position, the tension in the string is
A.
19.6 N
B.
1.96 N
C.
9.8 N
D.
Zero
Q382 Errorless Self Evaluation Test MCQ
An aeroplane moving horizontally at a speed of 200 m/s and at a height of $8.0 \times 10^{3}$ m is to drop a bomb on a target. At what horizontal distance from the target should the bomb be released
A.
7.234 km
B.
8.081 km
C.
8.714 km
D.
9.124 km
Q383 Errorless Self Evaluation Test MCQ
A ball of mass m is thrown vertically upwards. Another ball of mass 2m is thrown at an angle $\theta$ with the vertical. Both of them stay in air for same period of time. The heights attained by the two balls are in the ratio of
A.
2:1
B.
1:cos $\theta$
C.
1:1
D.
cos $\theta$ :1
Q384 Errorless Self Evaluation Test MCQ
A stone is projected from the ground with velocity 50 m/s at an angle of $30^{\circ}$ . It crosses a wall after 3 sec. How far beyond the wall the stone will strike the ground ( $g = 10 \, m/sec^{2}$ )
A.
90.2 m
B.
89.6 m
C.
86.6 m
D.
70.2 m