Question

The powerful motorcycle can accelerate from rest to 28 ms -1 in only seconds
( a ) What is its average acceleration?
( b ) How far does it travel in that time?

Answer 1

i think the question is incomplete.. as the final velocity is not given
and time also

Answer 2

GIVEN

• Initial velocity (u) = 0 m/s --(At rest)
• Final velocity (v) 28 m/s
• Time taken (t) = 4 seconds

TO FIND

• Acceleration (a)
• Distance travelled (s)

SOLUTION

• On using 1st equation of motion, we get,

➥ v = u + at

➱ 28 = 0 + a × 4

➱ 4a = 28

➱ a = 28/4

➱ a = 7 m/s²

Now,

• On using 2nd equation of motion, we get,

➥ s = ut + 1/2 at²

➱ s = 0 × 4 + 1/2 × 7 × (4)²

➱ s = 1/2× 7 × 16

➱ s = 7 × 8

➱ s = 56m

• Acceleration (a) = 7 m/s²
• Distance travelled (s) = 56 m