Q. No.A ball is traveling with uniform translatory motion. This means that:
1.
it is at rest.
2.
the path can be a straight line or circular and the ball travels with uniform speed.
3.
all parts of the ball have the same velocity (magnitude and direction) and the velocity is constant.
4.
the center of the ball moves with constant velocity and the ball spins about its center uniformly.
A cricket ball of mass 150 g has an initial velocity \(\small {u = \left(3 \hat{i} + 4 \hat{j} \right) \text {ms}^{- 1}}\) and a final velocity \(\small {v = - \left( 3 \hat{i} + 4 \hat{j} \right) \text{ms}^{- 1}}\), after being hit. The change in momentum (final momentum-initial momentum) is (in kgm/s)
1. \(\text {zero}\)
2. \(-\left ( 0.45\hat{i}+0.6\hat{j} \right ) \)
3. \(-\left ( 0.9\hat{i}+1.2\hat{j} \right ) \)
4. \(-5\left ( \hat{i} +\hat{j}\right ) \)
Conservation of momentum in a collision between particles can be understood from:
| 1. | conservation of energy |
| 2. | newton's first law only |
| 3. | newton's second law only |
| 4. | both Newton's second and third law |
A hockey player is moving northward and suddenly turns westward at the same speed to avoid an opponent. The force that acts on the player is:
| 1. | frictional force along westward |
| 2. | muscle force along southward |
| 3. | frictional force along south-West |
| 4. | muscle force a south-West |
A body of mass \(2~\text{kg}\) travels according to the law \(x \left( t \right) = pt + qt^2+ rt^3\) where,\(\) \(p = 3 ~\text{ms }^{−1 },\) \(q = 4 ~\text{ms }^{−2}\) and \(r = 5 ~\text{ms }^{−3}\). The force acting on the body at \(t = 2 ~\text{s }\) is
1. \(136~\text{N}\)2. \(134~\text{N}\)
3. \(158~\text{N}\)
4. \(68~\text{N}\)
A body with a mass of \(5\) kg is acted upon by a force \(\vec{F}=( -3\hat{i} +4\hat{j})\) N. If its initial velocity at \(t=0\) is \(\vec{v}= ( 6\hat{i} -12\hat{j} )\) m/s, the time at which it will just have a velocity along the Y-axis is:
1. never
2. \(10\) s
3. \(2\) s
4. \(15\) s
A car of mass \(m\) starts from rest and acquires a velocity along the east, \(v=v\mathrm{\hat{i}}(v>0)\) in two seconds. Assuming the car moves with uniform acceleration, the force exerted on the car is:
| 1. | \(mv/2 \) eastward and is exerted by the car engine. |
| 2. | \(mv/2\) eastward and is due to the friction on the tires exerted by the road. |
| 3. | more than \(mv/2\) eastward exerted due to the engine and overcomes the friction of the road. |
| 4. | \(mv/2\) exerted by the engine. |
In the figure, the coefficient of friction between the floor and body \(B\) is \(0.1.\) The coefficient of friction between bodies \(B\) and \(A\) is \(0.2.\) A force \(F\) is applied as shown on \(B.\) The mass of \(A\) is \(m/2\) and of \(B\) is \(m.\)
| (a) | The bodies will move together if \(F = 0.25\text{mg}\) |
| (b) | The \(A\) will slip with \(B\) if \(F = 0.5\text{mg}\) |
| (c) | The bodies will move together if \(F = 0.5\text{mg}\) |
| (d) | The bodies will be at rest if \(F = 0.1\text{mg}\) |
| (e) | The maximum value of \(F\) for which the two bodies will move together is \(0.45\text{mg}\) |
Which of the following statement(s) is/are true?
1. (a), (b), (d), (e)
2. (a), (c), (d), (e)
3. (b), (c), (d)
4. (a), (b), (c)
Mass \(m_{1}\) moves on a slope making an angle \(\theta\) with the horizontal and is attached to mass \(m_{2}\) by a string passing over a frictionless pulley as shown in the figure. The coefficient of friction between \(m_{1}\) and the sloping surface is \(\mu\).
| (a) | If \(m_{2} > m_{1} \text{sin} \theta \), the body will move up the plane. |
| (b) | If \(m_{2} > m_{1} (\text{sin} \theta +\mu \text{cos} \theta)\), the body will move up the plane. |
| (c) | If \(m_{2} < m_{1} (\text{sin} \theta +\mu \text{cos} \theta)\), the body will move up the plane. |
| (d) | If \(m_{2} < m_{1} (\text{sin} \theta -\mu \text{cos} \theta)\), the body will move down the plane. |
| 1. | (a), (d) | 2. | (a), (c) |
| 3. | (c), (d) | 4. | (b), (d) |
In figure a body \(A\) of mass \(m\) slides on a plane inclined at angle \(\left(\theta_{1}\right)\) to the horizontal and \(\mu\) is the coefficient of friction between \(A\) and the plane. \(A\) is connected by a light string passing over a frictionless pulley to another body \(B,\) also of mass \(m\), sliding on a frictionless plane inclined at an angle \(\left(\theta_{2}\right)\) to the horizontal.
| (a) | A will never move up the plane |
| (b) | A will just start moving up the plane when \(\mu = \dfrac{{\sin} \left(\theta\right)_{2} - {\sin} \left(\theta\right)_{1}}{{\cos} \left(\theta\right)_{1}}\) |
| (c) | For \(A\) to move up the plane, \(\left(\theta\right)_{2}\) must always be greater than \(\left(\theta\right)_{1}\) |
| (d) | \(B\) will always slide down with a constant speed |
Which of the following statement/s is/are true?
| 1. | (b, c) | 2. | (c, d) |
| 3. | (a, c) | 4. | (a, d) |
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