Learn in your speed, with individual attention - Teachoo Maths 1-on-1 Class

NCERT Questions

NCERT Question 1
Important

NCERT Question 2 Important

NCERT Question 3 Important

NCERT Question 4 Important

NCERT Question 5 Important You are here

NCERT Question 6 Important

NCERT Question 7 Important

NCERT Question 8

NCERT Question 9

NCERT Question 10 Important

NCERT Question 11 Deleted for CBSE Board 2024 Exams

NCERT Question 12 Important

NCERT Question 13

NCERT Question 14

NCERT Question 15 Important

NCERT Question 16 Important

NCERT Question 17 Important

NCERT Question 18 Important

Class 9

Chapter 9 Class 9 - Force and Laws Of Motion

Last updated at May 29, 2023 by Teachoo

NCERT Question 5 A truck starts from rest & rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 tonnes (Hint: 1 tonne = 1000 kg.) The truck starts from rest, ∴ Initial velocity = u = 0 m/s Distance travelled = s = 400 m Time taken = t = 20 s Since we have u, s and t, we can find acceleration by using 2nd equation of motion. s = ut + 1/2 at2 400 = 0 × 20 + 1/2 × a × (20)2 400 = 0 + 1/2 × a × 400 200 a = 400 a = 400/200 a = 2 m/s2 We know that, Force = mass × acceleration Given, Mass = 7 metric tonnes = 7 × 1000 kg = 7000 kg Acceleration = 2m/s2 Now, ∴ Force = Mass × Acceleration = 7000 × 2 = 14000 N