The ration of output work to input work expressed as a percentage is called <u>Efficiency</u>.
Answer:

So a=3.844 and b=5
Explanation:
Scientific notation requests to write a number using powers of ten as a factor accompanying a real number (a) between 1 and smaller than 10 that contains the digits to exactly represent the original number. So in this case, the number 384,400 can be written as:

with a=3.844, and "5" as the exponent of ten (so b=5)
<em>Given that:</em>
mass of the ball (m) = 0.5 Kg ,
ball strikes the wall (v₁) = 5 m/s ,
rebounds in opposite direction (v₂) = 2 m/s,
time duration (t) = 0.01 s,
<em> Determine the force (F) = ?</em>
We know that from Newton's II law,
<em>F = m. a</em> Newtons
(velocity acting in opposite direction, so <em>a = ( (v₁ + v₂)/t</em>
= m × (v₁ + v₂)/t
= 0.5 × (5 + 2)/0.01
= 350 N
<em>The force acting up on the ball is 350 N</em>