A 8 kg trolley moving at 7 m/s hits a stationary 1 kg trolley and they stick together. What is their speed afterwards?
Answer and explanation
Correct answer: B. 6.222 m/s
- Step 1: Momentum is conserved: 8 x 7 = (8+1) v.
- Step 2: v = 56/9 = 6.222 m/s.
Answer
6.222 m/s.
Why not the others: 7 m/s, 56 m/s and 3.5 m/s do not fit.
Practise more Mechanics.
Free questions with an explanation for every one, and full timed Tahsili SAAT (Saudi Arabia) mock tests.
More Mechanics questions
- A train moving at 15 m/s brakes with a constant deceleration of 5 m/s squared. What distance does it travel before stopping?
- A train moving at 15 m/s brakes with a constant deceleration of 8 m/s squared. What distance does it travel before stopping?
- A train moving at 25 m/s brakes with a constant deceleration of 4 m/s squared. What distance does it travel before stopping?
- A train moving at 30 m/s brakes with a constant deceleration of 6 m/s squared. What distance does it travel before stopping?
- A 6 kg crate is pulled along a rough floor by a force of 91 N. Friction is 23 N. What is the acceleration?
- A 6 kg crate is pulled along a rough floor by a force of 50 N. Friction is 9 N. What is the acceleration?