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. \(-5\left ( \hat{i} +\hat{j}\right ) \)

In the previous problem (3), the magnitude of the momentum transferred during the hit is:
1. zero
2. 0.75 kg-ms^–1
3. 1.5 kg-ms^–1
4. 14 kg-ms^–1

Conservation of momentum in a collision between particles can be understood from:

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:

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

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:

The motion of a particle of mass \(m\) is given by \(x=0\) for \(t<0 ~\text s\), \(x(t)=A~\text {sin}~4\pi t\) for \(0<t<(1/4) \text s ~(A>0)\), and \(x=0\) for \(t>(1/4) ~\text s\). Then:

Which of the following statement/s is/are true?

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 \(rn/2\) and of \(B\) is \(m.\)

Which of the following statement(s) is/are true?

A body of mass \(10\) kg is acted upon by two perpendicular forces, \(6\) N and \(8\) N. The resultant acceleration of the body is: