Answer:
Compared to the first student, the second student did twice as much work as the first student.
Explanation:
The work done by the first student will be equal to the Force exerted by the backpack on the student carrying it multiplied by one mile (Distance). The work done by the second student will be equal to the Force exerted by the backpack on the student carrying it multiplied by two miles (Distance).
Answer:

Explanation:
What problem says can be written mathematically as:

Where:

The problem itself it's really simple, we only need to replace the data provided in the previous equation, but first, let's convert the units of the velocity from cm/s to m/s because we have to work with the same units and working in meters is the most apropiate action, because is the base unit of length in the International System of Units:

Now, we can replace the data in the equation and find the time it will take the bird to travel 3.7 m:

Solving for t, multiplying by t both sides, and dividing by 0.52 both sides:

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:
1. The elephant has more kinetic energy at this speed and mass. It has 4,500 J more KE.
2. The elephant would have to go at a speed of 2.5 m/s to reach the same KE as the cheetah.
Explanation:
You would use the formula KE=1/2mv^2.
This formula would be filled in and completed twice, once for the elephant and once for the cheetah.
Cheetah:
KE = 1/2 (40) (25) ^2
KE = 12,500 J
Elephant:
KE = 1/2 (4,000) (2) ^2
KE = 8,000 J
This shows that the cheetah has more KE.
Then you would subtract the elephants amount of J from the cheetahs to find the difference.
Difference = 12,500 J - 8,000 J
Difference = 4,500 J
I hoped this helped with the first part :)
For the second part:
To find the speed the elephant would have to run you would fill in and complete the equation once more with different distance results.
KE = 1/2 (4,000) (2.5) ^2
KE= 12,500 J