Answer:
Explanation:
95.0 km/hr = 26.39 m/s
65 km/hr = 18.06 m/s
Circumference of a tire is 0.9π m
77 revolutions is a distance of
77(0.9π) = 69.3π m
v² = u² + 2as
a = (v² - u²) / 2s
a = (18.06² - 26.39²) / (2(69.3π))
a = -0.85 m/s²
s = (v² - u²) / 2a
s = (0² - 26.39²) / 2(-0.85)
s = 409 m
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
The heat required to convert the unknown substance X from one phase to another is 1600 J times the specific heat of that substance.
Explanation:
The heat energy required to convert a substance or to heat up or increase the temperature of a substance can be obtained from the specific heat formula.
As per this formula, the heat energy applied should be equal to the product of mass of the substance with temperature gradient and also with specific heat of the substance. Basically, the heat provided to increase or convert a substance should be more than the specific heat of the substance.

Since, here the mass of the substance X is given as m = 20g and the temperature change is given from -10°C to 70°C.
Then ΔT = (70-(-10))=70+10=80°C.
As the substance is unknown, the specific heat of that substance can also not be determined. Hence keep it as C.

Q = 1600C J
Thus, the heat required to convert the unknown substance X from one phase to another is 1600 J times the specific heat of that substance.
Answer: (C) Slide against each other
Explanation:
Think about rubbing our palms together, and they get warm that right there is friction.
Current can vary in different branches of a circuit