The last option would be I think
Complete question is: While running, a person dissipates about 0.60 J of mechanical energy per step per kilogram of body mass. If a 60-kg person develops a power of 70 W during a race, how fast is the person running? (Assume a running step is 1.5 m long).
Answer: The person running at a speed of 2.91 m/s.
Explanation:
Given: Mass of runner = 60 kg
Runner dissipates = 0.6 J/kg per step
Average power = 70 W
1 step = 1.50 m
Energy dissipated by the runner is as follows.
Formula used to calculate the value of one step 'S' is as follows.
It is known that average velocity is equal to the total distance divided by time interval.
So, total distance for the given situation is as follows.
Hence, speed of the person is calculated as follows.
Thus, we can conclude that the person running at a speed of 2.91 m/s.
Answer:
Reflection is when light bounces of an object. If the surface is smooth and shiny, like glass, water or polished metal, the light will reflect at the same angle as it hit the surface.
Force of gravity on an object is the weight of the object and is given by mass times accerelation due to gravity. The accerelation due to gravity is the accerelation of an object in free fall and is given by 9.8m/s^2. Given that the force of gravity acting on a child's mass on earth is 490 newtns, i.e. F = mg which means that 490 newtons = 9.8 times mass. Therefore, mass of the child is 490 / 9.8 = 50 kg.
Answer: The plant will taller than its actual height.