K.E. in Relativistic Physics

Q. If 2 persons A and B of mass M are sitting inside a bus moving with a constant velocity v. Person C is standing on the road watching the bus go.What would be the Kinetic Energy of A told by B and C respectively?

1. $\frac{\left(m{v}^2\right)}{2}$, $\frac{\left(m{v}^2\right)}{2}$
2. 0, $\frac{\left(m{v}^2\right)}{2}$
3. $\frac{\left(m{v}^2\right)}{2}$, 0
4. 0, 0

Q. A time varying net force acts on a $8.0kg$ block. Particle's displacement is given by $X=A{t}^2+Bt+C$ $(A=2m/s^2,B=6m/s,C=4m)$. Find work done on the block in first $4s$ of motion.

1. 1947
2. 1857
3. 1792
4. 1869

Q. A block of mass m is given a kick on frozen pond, imparting an initial speed of $v=4m/s$. Coefficient of friction between block and ice is ${\mu }_K=0.5$. Find the distance the block moves before stopping.

1. 2.4 m
2. 0.8 m
3. 3.2m
4. 1.6 m

Q. The kinetic energy of a particle moving along a circle of radius $R$ depends on distance $\left(s\right)$ as $K=A{s}^2$ where $A$ is a constant.

The tangential force acting on the particle is

1. $mAs$
2. $2mAs$
3. $As$
4. $2As$

Q. A time varying net force acts on a $8.0kg$ block. Particle's displacement is given by $X=A{t}^2+Bt+C$ $(A=2m/s^2,B=6m/s,C=4m)$. Find work done on the block in first $4s$ of motion.

1. 1947
2. 1857
3. 1792
4. 1869