Answer:
When extra energy is added
Explanation:
When the ball is released from rest and swings back towards your face, it will only pass closer to the end of the nose as per the initial conditions. However, when extra energy is added to the ball, it strikes the nose since its velocity and heights are increased. Therefore, the only condition under which the ball hits your nose is when extra energy is added to the system.
<span>We know that an object in moving with acceleration follow the rule according that
the distance covered will be : d = Vi*t + 1/2*a*t^2
where d is distance, Vi is initial speed, and a is acceleration
Then after 1 km which is 1000 metres we have:
1000 = Vi *71.2 + 1/2*0.0499*(71.2)^2
Vi = (1000-1/2*0.0499*(71.2)^2)/71.2 = 1000/71.2 - 1/2*0.0499*71.2 = 12.27 m/s
Then the car was going at 12.27 m/s when started to accelerate.</span>