Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
36.5k views
in Physics by (72.3k points)

A body of mass 0.3 kg is taken up an inclined plane to length 10 m and height 5 m and then allowed to slide down to the bottom again. The coefficient of friction between the body and the plane is 0.15. What is the 

(i) work done by the gravitational force over the round trip. 

(ii) work done by the applied force over the upward journey. 

(iii) work done by frictional force over the round trip. 

(iv) kinetic energy of the body at the end of the trip. How is the answer to 

(iv) related to the first three answer ?

1 Answer

+1 vote
by (70.7k points)
selected by
 
Best answer

(i) W = FS = – mg sin q × h = – 14·7 J is the W.D. by gravitational force in moving the body up the inclined plane. 

W′ = FS = + mg sin θ × h = 14·7 J is the W.D. by gravitational force in moving the body down the inclined plane. 

∴ Total W.D. round the trip, W1 = W + W′ = 0. 

(ii) Force needed to move the body up the inclined plane, 

F = mg sin θ + fk 

= mg sin θ + µk

= mg sin θ + µk mg cos θ 

∴ W.D. by force over the upward journey is 

W2 = F × l = mg (sin θ + µk cos θ) l 

= 18·5 J 

(iii) W.D. by frictional force over the round trip, 

W3 = – fk (l + l) = – 2fk

= – 2µk mg cos θ l = – 7·6 J 

(iv) K.E. of the body at the end of round trip 

= W.D. by net force in moving the body down the inclined plane 

= (mg sin θ – µk mg cos θ) l 

= 10·9 J 

⇒ K.E. of body = net W.D. on the body.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...