Question

a car moving with uniform accelaration, cover 12 m in 3 sec and 20 m in 5 sec . Find the velocity of the car after 10 sec.
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Answer 1

Explanation:

displacement for the n

th

second is given by ,

S

n

=u+

2

1

a(2n−1)

so from the question we get ,

S

3

=u+

2

1

a(2×3−1)⇒12=u+(5/2)a....(1)

S

5

=u+

2

1

a(2×5−1)⇒20=u+(9/2)a...(2)

subtracting eq1 from eq 2 we get

8=2a⇒a=4

usin this in eq 1 we get value of u=2

now for solving for the eighth second ,

S

8

=2+

2

1

×4×(2×8−1)=32m

you can see by picture