Answer:
<em>The initial speed of the sprinter was 2.2 m/s</em>
Explanation:
<u>Constant Acceleration Motion</u>
It's a type of motion in which the velocity of an object changes by an equal amount in every equal period of time.
The following relation applies:
Where a is the constant acceleration, vo the initial speed, vf the final speed, and t the time.
The sprinter speeds up from an unknown initial speed to vf=3 m/s in t=2 seconds with an acceleration of 
.
To find the initial speed, we solve the equation for vo:
Substituting the values:
The initial speed of the sprinter was 2.2 m/s
Answer:
The change in momentum is 28265.71 kg-m/s.
Explanation:
Given that,
Mass of a car, m = 877 kg
Initial velocity of the car, u = 0 (at rest)
Final velocity of the car, v = 116 km/h = 32.23 m/s
Time, t = 0.951 s
We need to find the change in momentum produced by the force. It can be calculated as the difference of final momentum and the initial momentum.
So, the change in momentum is 28265.71 kg-m/s.
Relative density, or specific gravity, is the ratio of the density of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest; for gases, the reference is air at room temperature.
