Well this question looks like it makes some assumptions. So assuming that both cars have the same mass and experience the same wind resistance regardless of speed and same internal frictions, then we could say "The car that finishes last has the lowest power". The reason is that for a given race the cars must overcome losses associated with motion. Since they all travel the same distance, the amount of work will be the same for both. This is because work is force times distance. If the force applied is the same in both cases (identical cars with constant wind resistance) and the distance is the same for both (a fair race track) then W=F·d will be the same.
Power, however, is the work done divided by the time over which it is done. So for a slower car, time t will be larger. The power ratio W/t will be smaller for the longer time (slower car).
Complete Question:
One simple model for a person running the 100 m dash is to assume the sprinter runs with constant acceleration until reaching top speed, then maintains that speed through the finish line. If a sprinter reaches his top speed of 11.5 m/s in 2.24 s, what will be his total time?
Answer:
total time = 6.24 s
Explanation:
Using the equation of motion:
v = u + at
initial speed, u = 0 m/s
v = 11.5 m/s
t = 2.24 s
11.5 = 0 + 2.24a
a = 11.5/2.24
a = 5.13 m/s²
For the total time spent by the sprinter:
s = ut + 0.5at²
100 = 0.5 * 5.13 * t²
t² = 100/2.567
t² = 38.957
t = √38.957
t = 6.24 s
Answer:
A) 5 m/s/s
Explanation:
<u>Given the following data;</u>
Initial velocity = 10m/s²
Final velocity = 20m/s²
Time, t = 2 seconds.
In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.
This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.
Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.
Mathematically, acceleration is given by the equation;
Substituting into the equation, we have;
<em>Acceleration, a = 5m/s²</em>
Answer:
(a) 
(b) 
(c) 
Solution:
As per the question:
Mass of Earth, 
Mass of Moon, 
Mass of Sun, 
Distance between the earth and the moon, 
Distance between the earth and the sun, 
Distance between the sun and the moon, 
Now,
We know that the gravitational force between two bodies of mass m and m' separated by a distance 'r' is given y:
(1)
Now,
(a) The force exerted by the Sun on the Moon is given by eqn (1):
(b) The force exerted by the Earth on the Moon is given by eqn (1):
(c) The force exerted by the Sun on the Earth is given by eqn (1):
Answer:
12.24 m/s
Explanation:
Speed: This can be defined as the rate of change of distance with time. The S.I unit of speed is m/s.
Using the formula,
a = v/t................ Equation 1
Where a = acceleration of the sprinter, v = speed of the sprinter, t = time.
making v the subject of the equation,
v = at ................. Equation 2
Given: a = 5.1 m/s², t = 2.4 s.
Substitute into equation 2
v = 5.1(2.4)
v = 12.24 m/s.
Hence, the speed of the sprinter = 12.24 m/s
