Answer:
t=7.33 s
Explanation:
According to Newton's second law:

because we don't want the box to slide, the acceleration has to be zero.

we know that:

Now having the acceleration, we can use the following formula.

Answer:
120,000J
Corrected question;
In one hour, coal supplies 500 000 J of energy. The wasted energy amounts to 380 000 J. How much useful energy is produced in one hour?
Explanation:
Given;
Total energy Et = 500,000 J
Wasted Energy Ew = 380,000J
The amount useful energy is the amount of energy that is available for supply.
This can be derived by subtracting the wasted energy from the total energy.
Useful energy = Total Energy - wasted energy
Eu = Et - Ew
Substituting the given values;
Eu = 500,000J - 380,000
Eu = 120,000 J
The amount of useful energy produced in one hour is 120,000 J
D transferring electrons because that causes electricity
The average velocity of a car that travels 450 km north in 9.0 h is 5.0 x 10 km/h
Answer:
No
Explanation:
The supplied information about the object and train is incomplete. Acceleration is the rate at which the velocity of a body changes with time. Here the velocity and time is not given