363185
In a lift moving up with an acceleration of \(5\,m{s^{ - 2}}\), a ball is dropped from a height of \(1.25\,m\). The time taken by the ball to reach the floor of the lift is ______ (nearly) (\(g = 10\,m{s^{ - 2}}\))
1 0.3 second
2 0.2 second
3 0.16 second
4 0.4 second
Explanation:
Time taken by the ball to reach the floor is \(t = \sqrt {\frac{{2h}}{{a + g}}} \) Here, \(h = 1.25\,m,g = 10\,m{s^{ - 2}},a = 5\,m{s^{ - 2}}\) \(\therefore \,t = \sqrt {\frac{{2 \times 1.25\,m}}{{(5 + 10)m{s^{ - 2}}}}} = 0.4\,s\)
KCET - 2013
PHXI05:LAWS OF MOTION
363186
The apparent weight of a freely falling person is
1 Zero
2 Increased
3 Decreased
4 Constant
Explanation:
Conceptual Question
PHXI05:LAWS OF MOTION
363187
A bob is hanging inside a car through a massless string as shown in figure. The car is moving with constant acceleration \(a\), horizontally The bob makes an angle \(\theta \) with the vertical at equilibrium. Then which of the following statement is correct?
1 \(\theta \) is independent of \(a\)
2 With increase of \(a\), \(\theta \) will decrease
3 With decrease of \(a\), \(\theta \) will decrease
4 None of these
Explanation:
\(\tan \theta = \frac{a}{g}\) So, \(\theta \) is directly proportional to \(a\). If \(a\) decreases then \(\theta \) decreases.
363185
In a lift moving up with an acceleration of \(5\,m{s^{ - 2}}\), a ball is dropped from a height of \(1.25\,m\). The time taken by the ball to reach the floor of the lift is ______ (nearly) (\(g = 10\,m{s^{ - 2}}\))
1 0.3 second
2 0.2 second
3 0.16 second
4 0.4 second
Explanation:
Time taken by the ball to reach the floor is \(t = \sqrt {\frac{{2h}}{{a + g}}} \) Here, \(h = 1.25\,m,g = 10\,m{s^{ - 2}},a = 5\,m{s^{ - 2}}\) \(\therefore \,t = \sqrt {\frac{{2 \times 1.25\,m}}{{(5 + 10)m{s^{ - 2}}}}} = 0.4\,s\)
KCET - 2013
PHXI05:LAWS OF MOTION
363186
The apparent weight of a freely falling person is
1 Zero
2 Increased
3 Decreased
4 Constant
Explanation:
Conceptual Question
PHXI05:LAWS OF MOTION
363187
A bob is hanging inside a car through a massless string as shown in figure. The car is moving with constant acceleration \(a\), horizontally The bob makes an angle \(\theta \) with the vertical at equilibrium. Then which of the following statement is correct?
1 \(\theta \) is independent of \(a\)
2 With increase of \(a\), \(\theta \) will decrease
3 With decrease of \(a\), \(\theta \) will decrease
4 None of these
Explanation:
\(\tan \theta = \frac{a}{g}\) So, \(\theta \) is directly proportional to \(a\). If \(a\) decreases then \(\theta \) decreases.
363185
In a lift moving up with an acceleration of \(5\,m{s^{ - 2}}\), a ball is dropped from a height of \(1.25\,m\). The time taken by the ball to reach the floor of the lift is ______ (nearly) (\(g = 10\,m{s^{ - 2}}\))
1 0.3 second
2 0.2 second
3 0.16 second
4 0.4 second
Explanation:
Time taken by the ball to reach the floor is \(t = \sqrt {\frac{{2h}}{{a + g}}} \) Here, \(h = 1.25\,m,g = 10\,m{s^{ - 2}},a = 5\,m{s^{ - 2}}\) \(\therefore \,t = \sqrt {\frac{{2 \times 1.25\,m}}{{(5 + 10)m{s^{ - 2}}}}} = 0.4\,s\)
KCET - 2013
PHXI05:LAWS OF MOTION
363186
The apparent weight of a freely falling person is
1 Zero
2 Increased
3 Decreased
4 Constant
Explanation:
Conceptual Question
PHXI05:LAWS OF MOTION
363187
A bob is hanging inside a car through a massless string as shown in figure. The car is moving with constant acceleration \(a\), horizontally The bob makes an angle \(\theta \) with the vertical at equilibrium. Then which of the following statement is correct?
1 \(\theta \) is independent of \(a\)
2 With increase of \(a\), \(\theta \) will decrease
3 With decrease of \(a\), \(\theta \) will decrease
4 None of these
Explanation:
\(\tan \theta = \frac{a}{g}\) So, \(\theta \) is directly proportional to \(a\). If \(a\) decreases then \(\theta \) decreases.