Arailway car having a total mass of 5.8 × 105 kg, moving with a speed of 9.1 km/h, strikes another car that has a mass of 8.7 × 105 kg and is initially at rest. the speed of the coupled cars after the collision is

a) 9.1 km/h.
b) 7.2 km/h.
c) 3.6 km/h.
d) 1.8 km/h.
e) 4.2 km/h

Final speed of both the cars, V = 3.28 km/h

Explanation:

It is given that,

Mass of the railway car,

Initial speed of the railway car,

Mass of another car,

Initial speed of another car,

To find,

The speed of the coupled cars after the collision.

Solution,

It is a case of inelastic collision in which the linear momentum before and after the collision remains same. Let V is the coupled velocity of both of the cars. So,

V = 1.011 m/s

or

V = 3.28 km/h

So, the speed of the coupled cars after the collision is 3.28 km/h. Hence, this is the required solution.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards