Question

a body moves 5m in the 3rd second and moves 9m in the 7th second. find the distance moved by the body between time= 5s and time= 8s

Answer 1

Answer:

A body moving with a uniform acceleration describes 12 m in the third second of its motion and 20 m in the fifth second. Find the distance covered in the length second.

Hard

Answer

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

Answer 2

Answer:

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