A man 2 m high walks at a uniform speed of 5km/hr away from a lamp post 6 m high. Find the rate at which the length of his shadow increases?

A girl of height 120cm is walking away from the base of a lamp post at a speed of 0.6 m/sec. . If the lamp is 3.6 m above the ground level, then find the length of her shadow after 4 seconds.

A man is moving away from a tower 41.6 m high at the rate of 2 m/sec. Find the rate at which the angle of elevation of the top of tower is changing, when he is at a distance of 30m from the foot of the tower. Assume that the eye level of the man is 1.6m from the ground.

A spherical iron ball 10cm in radius is coated with a layer of ice of uniform thickness that melts at a rate of 50c m^3//m in . When the thickness of ice is 5cm, then find the rate at which the thickness of ice decreases.

A lamp of negligible height is placed on the ground l_1 away from a wall. A man l_2m tall is walking at a speed of (l_1)/(10)m//s from the lamp to the nearest point on the wall. When he is midway between the lamp and the wall, the rate of change in the length of this shadow on the wall is -(5l_2)/2m//s (b) -(2l_2)/5m//s -(l_2)/2m//s (d) -(l_2)/5m//s

A lamp of negligible height is placed on the ground l_1 away from a wall. A man l_2m tall is walking at a speed of (l_1)/(10)m//s from the lamp to the nearest point on the wall. When he is midway between the lamp and the wall, the rate of change in the length of this shadow on the wall is -(5l_2)/2m//s (b) -(2l_2)/5m//s -(l_2)/2m//s (d) -(l_2)/5m//s

A concave mirror forms an image of 20 cm high object on a screen placed 5.0 m away from the mirror. The height of the image is 50 cm. Find the focal length of the mirror and the distance between the mirror and the object.

An aeroplane is flying horizontally at a height of 2/3k m with a velocity of 15 km/h. Find the rate at which it is receding from a fixed point on the ground which it passed over 2 min ago.

A man at a speed of 6 km/hr for 1 km and 8 km/hr for the next 1 km. What is t his average speed for the walk of 2 km?