Question

a bus accelerates at 2m/s² for first 10s after start and retards at 1m/s² for next 10s.Find the total distance covered by bus

Answer 1

let s1 be the distance travelled during its acceleration ...a=2 t1=10

we know that s1=ut+1/2at²

since u=0

s1=1/2(2)(10)(10)

s1=100m and also v=u+at
v=20m/s


now let s2 be the distance travelled during its declaration ...a=-1,u=20,t=10

now s2 = 200-50=150


total distance travelled =100+150=250m


I hope this will help u ;)

Answer 2

Answer:

The answer is 150 meters.

Explanation:

We know that,

u=0m/s

a=2m/s2

t=10s

for case 1.

Therefore, using the second equation of motion,

s=ut +1/2at2

s=1/2*2*100

=100metres.

Case 2.

v=0m/s because the train is deccelerating.

a=-1m/s

t=10s

to find u,

v=u + at

0=u + -1*10

Therefore u=10m/s

using second equating of motion,

s=10*10 +1/2*-1*100

=50m

Therefore,

100+50=150metres.

Thanks.