NCERT Class9 Science Solutions: Chapter 8Motion Part 5
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Question 20:
An object starting from rest travels in first and in next. What will be the velocity after from the start?
Answer:
Since acceleration is the same, we have
Question 21:
Using following data, draw time  displacement graph for a moving object:
Time (s)  0  2  4  6  8  10  12  14  16 
Displacement (m)  0  2  4  4  4  6  4  2  0 
Use this graph to find average velocity for first, for next and for last .
Answer:
Average velocity for first 4 s.
For next 4 s
(or as x remains the same from 4 to 8 seconds, velocity is zero)
For last 6 s
Question 22:
An electron moving with a velocity of enters into a uniform electric field and acquires a uniform acceleration of in the direction of its initial motion.

Calculate the time in which the electron would acquire a velocity double of its initial velocity.

How much distance the electron would cover in this time?
Answer:
Given initial velocity
And acceleration

Final velocity
To find

Using