<span>a = (v2 - v1)/t= acceleration formula
a = (70 - 0)/7
a = 10 km/hr/sec
-----
It's better to use as few units as possible.
10 km/hr = 10 km*1000 m/km/(1 hr*3600 sec/hr) = 25/9 m/sec
a= 25/9 m/sec/se</span>
The work done on the car is -20 J.
Work done on the car is negative, meaning that the car actually does work on the external system.
<h3>Energy and law of conservation of energy</h3>
- Energy is the ability to do work
- the law of conservation of energy states that the total energy in a system is conserved
From the law of conservation of energy, the initial energy of the car before it moves down the road remains constant or unchanged.
- Initial energy = 100 J
- Initial energy = Final energy - work done on car
- Final Energy = Work done on car + initial energy
80J = Work done on car + 100 J
Work done on car = 80 - 100J
Work done on car = -20 J
Hence, the work done on the car is -20 J
Work done on car is negative.
Since work done on the car is negative, it means that the car actually does work on the external system. Hence, the decrease in the energy of the car.
Learn more about energy and work at: brainly.com/question/13387946
Answer:

Explanation:
The period of a physical pendulum is:



The length of the leg is approximately the height of the person:

The period is:


Answer:
Measuring, comparing and estimating liquid volumes are taught using metric units like liters and milliliters and customary units like quart, pints, gallons and more. Capacity is actually the amount of liquid in the container, which is also the volume of a liquid.
Explanation:
Answer:
Point A
Explanation:
The work done by stretching or compressing a spring is given by E=1/2kx²
The potential energy is numerically equal to the work done.
This means that the higher the bigger the value of the extension, x, the higher the energy contained.
In this scenario the modulus of x is considered.
Among the given values of x the modulus of -5 is the largest.
thus it gives the highest value of energy.