Home › ICSE Class 9 › physics › Motion in One Dimension › A car at 36 km/h is brought to rest by uniform r…
A car at 36 km/h is brought to rest by uniform retardation in 50 metres. The retardation magnitude is:
A0.5 m per second squared
B1.0 m per second squared
C1.5 m per second squared
D2.0 m per second squared
Answer & Solution
Correct answer: B. 1.0 m per second squared
1. Convert 36 km/h to m per second: 36 × 1000 / 3600 = 10 m per second.
2. The car finally stops, so v = 0; initial speed u = 10 m per second.
3. Distance to stop s = 50 m.
4. Use v² − u² = 2as: 0 − 100 = 2 × a × 50.
5. So a = −1.0 m per second squared.
6. The magnitude of retardation is 1.0 m per second squared.
_Source: Selina Concise Physics ICSE Class 9, Ch 2 'Motion in One Dimension' (aplustopper.com extract)_
Related questions
A stone is thrown straight up with initial velocity 20 m per second. Taking g = 10 m per sA body has zero average velocity over an interval. Which conclusion is FORCED?A body accelerates from 5 m per second to 25 m per second over 4 seconds. The distance covA stone is dropped from rest. After 2 seconds its velocity is approximately:On a velocity-time graph, the area under the curve represents:A car decelerates uniformly from 20 m per second to rest in 4 seconds. The retardation is:On a displacement-time graph, what does the slope of the line represent?Which equation gives displacement in terms of initial velocity, acceleration and time?