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Question
Figure shows the distance-time graph for the motion of two vehicles A and B. Which one of them is moving faster?
Figure: Distance-time graph for the motion of two cars
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Solution
The speed is given by the relation
speed = `" distance travelled" / "time taken"`
This relation shows that the speed of a vehicle is high if it covers the maximum distance in a given time interval. To compare the distance, draw a line perpendicular to the time axis, as shown in the following distance-time graph
The graph clearly shows that for a given time t, vehicle A covers more distance than vehicle B. So, vehicle A is moving faster than vehicle B.
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What is the nature of the distance-time graphs for uniform and non-uniform motion of an object?
Show the shape of the distance-time graph for the motion in the following case:
A car parked on a side road.
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Figure (a) shows the displacement-time graph for the motion of a body. Use it to calculate the velocity of the body at t = 1 s, 2 s and 3 s, and then draw the velocity-time graph in Figure (b) for it.
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| (a) | (b) |
A body moves along a straight road with a speed of 20 m/s and has a uniform acceleration of 5 m/s2. What will be its speed after 2 s?
Complete the data of the table given below with the help of the distance-time graph given in the figure.
| Distance (m) | 0 | 4 | ? | 12 | ? | 20 |
| Time (s) | 0 | 2 | 4 | ? | 8 | 10 |
Distance between Bholu’s and Golu’s house is 9 km. Bholu has to attend Golu’s birthday party at 7 o’clock. He started from his home at 6 o’clock on his bicycle and covered a distance of 6 km in 40 minutes. At that point, he met Chintu and he spoke to him for 5 minutes and reached Golu’s birthday party at 7 o’clock. With what speed did he cover the second part of the journey? Calculate his average speed for the entire journey.
Boojho goes to the football ground to play football. The distance-time graph of his journey from his home to the ground is given in the figure.
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- Is the motion between 0 to 4 minutes uniform or non-uniform?
- What is his speed between 8 and 12 minutes of his journey?
Assertion: The slope of the distance-time graph of a body moving with high speed is steeper than the slope of the distance-time graph of a body with low velocity.
Reason: Slope of distance-time graph = speed of the body.
