Given below are some speed-time graphs. In which of the graphs, (a) speed is constant. (b) speed is increasing (c) speed is decreasing (d) What happens in (iv)? (e) What happens in (v)?

(a) Speed is constant in speed-time graph (iii). It is not changing with time. (b) Comparing all graphs, speed is ever increasing in speed-time graph (i). As, there is a uniform increase in speed, the slope of the graph, i.e, acceleration is uniform or constant. (c) Comparing all graphs, speed is ever decreasing in speed-time graph (ii). There is a uniform decrease in speed. (d) The speed-time graph (iv) has three parts. In the first part the speed increases uniformly. In the second part the speed is constant. In the third part the speed decreases to zero. (e) According to speed-time graph (v), the speed decreases non-uniformly, and has non-uniform retardation.

A car is moving on a straight road with uniform acceleration. The speed of the car varies with time as follows: Time ( s ) 0 2 4 6 8 10 Speed ms - 1 4 8 12 16 20 24 Draw the speed-time graph by choosing a convenient scale. Determine from it: The distance traveled by the car in 10 seconds.

The speed-time graph of given data is: Where, X axis represents time in seconds ( 1 block = 2 seconds ) Where, Y axis represents speed in ms - 1 ( 1 block = 2 ms - 1 ) From the graph, Initial velocity, u = 4 ms - 1 Final velocity, v = 24 ms - 1 Time, t = 10 s Acceleration is given as: a = v - u t = 24 - 4 10 = 20 10 = 2 m / s 2 Using equation of motion, v 2 = u 2 + 2 as s = v 2 - u 2 2 a = 24 2 - 4 2 2 × 2 = 576 - 16 4 = 560 4 = 140 m

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Physics For Class 9>Chapter 1 - Motion>Exercise

Amisha Singh Solutions for Chapter: Motion, Exercise 2: Exercise

Author:Amisha Singh

Amisha Singh Physics Solutions for Exercise - Amisha Singh Solutions for Chapter: Motion, Exercise 2: Exercise

Attempt the practice questions on Chapter 1: Motion, Exercise 2: Exercise with hints and solutions to strengthen your understanding. Physics For Class 9 solutions are prepared by Experienced Embibe Experts.