NEET | 2017GravitationHard

Question

Consider a drop of rain water having mass 1 g falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take 'g' constant with a value 10 m/s2. The work done by the (i) gravitational force and the
(ii) resistive force of air is :-

Options

A.

(i) 1.25 J     (ii) – 8.25 J

B.

(i) 100 J     (ii) 8.75

C.

(i) 10 J      (ii) – 8.75 J

D.

(i) – -10 J      (ii) –- 8.25 J

Solution

Work done by the gravity (Wg) = mgh
= 10-3 × 10 × 10-3 = 10 J
By work–energy theorem = Wg + Wres = ∆KE
10 + Wres = 12×10-3 × (50)2
Wres =  - 8.75 J

Create a free account to view solution

View Solution Free
Topic: Gravitation·Practice all Gravitation questions

More Gravitation Questions

A planet is revolving around the sun is an elliptical orbit as shown in figure. Select correct alternative(s)...A simple pendulum has a time period T1 when on the earth′s surface and T2 when taken to a height R above the earth...Two spherical planets P and Q have the same uniform density ρ, masses MP and MQ and surface areas A and 4A respecti...The escape velocity from the earth is 11.2 km/sec. The escape velocity from a planthaving twice the radius and the same ...If W1, W2 and W3 represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respect...