Advertisements
Advertisements
प्रश्न
A train starting from rest picks up a speed of 20 ms−1 in 200 s. It continues to move at the same rate for the next 500 s and is then brought to rest in another 100 s.
- Plot a speed-time graph.
- From graph calculate
(a) uniform rate of acceleration
(b) uniform rate of retardation
(c) total distance covered before stopping
(d) average speed.
Advertisements
उत्तर
(i)
(ii)
(a) Uniform rate of acceleration = Slope of v.t. graph from O to A.
= `"AE"/"OE"=20/200` = 0.1 ms−2
(b) Uniform rate of retardation = Slope of v.t. graph from BC
= `"BD"/"CD"=20/100` = 0.2 ms−2
(c) Total distance covered before stopping
= ar(ΔOAE) + ar(ΔABDE) + ar(ΔBCD)
= `1/2xx"OE"xx"AE"+"AE"xx"ED" + 1/2xx"BD"xx"DC"`
= `1/2xx200xx20+20xx500+1/2xx20xx100`
= 2000 + 10000 + 1000
= 13000 m
= 13 km
(d) Average speed = `"Total distance covered"/"Total time taken"=13000/800`
= `130/8`
= 16.25 ms−1
APPEARS IN
संबंधित प्रश्न
Three speed-time graphs are given below :
Which graph represents the case of:
(i) a cricket ball thrown vertically upwards and returning to the hands of the thrower ?
(ii) a trolley decelerating to a constant speed and then accelerating uniformly ?
What does the slope of a displacement-time graph represent?
Draw a displacement-time graph for a boy going to school with uniform velocity.
A body at rest is thrown downward from the top of the tower. Draw a distance – time graph of its free fall under gravity during the first 3 seconds. Show your table of values starting t = 0 with an interval of 1 second, (g = 10 ms−2).
From the diagram given below, calculate distance covered by body.
Interpret the following graph:
Which of the following graphs represents a motion with negative acceleration?
Its time-displacement graph is a straight line.
Draw velocity-time graph to show:
Deceleration
Write a sentence to explain the shape of graph.
The area under velocity – time graph represents the ______
