A ball is thrown up with a speed of 30 m/s and caught when it comes back down. You can ignore air resistance.

An elevator car has a mass of 750 kg, and its three passengers have a combined mass of 135 kg. If the elevator and its passenger

joja [24]

Answer:

The change in gravitational potential energy is -1.80x10⁵ J.

Explanation:

The change in gravitational potential energy is given by:

$\Delta E_{p} = E_{p_{f}} - E_{p_{i}}$

$\Delta E_{p} = mgh_{f} - mgh_{i}$

Where:

"i" is for final and "f" for final

m: is the mass

g: is the gravity = 9.81 m/s²

h: is the height

For the car and the passengers we have:

$\Delta E_{p} = m_{T}g(h_{f} - h_{i}) = (750 kg + 135 kg)9.81 m/s^{2}(0 - 20.7 m) = -1.80 \cdot 10^{5} J$

The minus sign is because when the elevator car and the passengers are up they have a bigger gravitational potential energy than when they are in the ground.

Therefore, the change in gravitational potential energy is -1.80x10⁵ J.

I hope it helps you!

3 0

3 years ago

Why is it better to breathe through the nose than the mouth?

Citrus2011 [14]

You could get sick by breathing throw your mouth and you have a less chance of getting sick by breathing throw your nose.

3 0

3 years ago

A person on a cruise ship is doing laps on the promenade deck. On one portion of the track the person is moving north with a spe

Aleksandr-060686 [28]

The direction of motion of the person relative to the water is 16.7° north of east.

Why?

We can solve the problem by applying the Pitagorean Theorem, where the first speed (to the north) and the second speed (to the east) corresponds to two legs of the right triangle formed with them. (north and east directions are perpendicular each other)

We can calculate the angle that give the direction using the following formula:

$Tan(\alpha)=\frac{NorthSpeed}{EastSpeed}\\\\Tan(\alpha)^{-1}=Tan(\frac{NorthSpeed}{EastSpeed})^{-1}\\\\\alpha=Tan(\frac{NorthSpeed}{EastSpeed})^{-1}$

Now, substituting the given information we have:

$alpha=Tan(\frac{NorthSpeed}{EastSpeed})^{-1}$

$\alpha =Tan(\frac{3.6\frac{m}{s} }{12\frac{m}{s} })^{-1}\\\\\alpha =Tan(0.3)^{-1}=16.69\°(North-East)=16.7\°(North-East)$

Hence, we have that the direction of motion of the person relative to the water is 16.7° north of east.

Have a nice day!

7 0

3 years ago

One hazard of space travel is debris left by previous missions. There are several thousand objects orbiting Earth that are large

Eva8 [605]

Answer:

6666.67 Newtons

Explanation:

The formula F=ma (force is equal to mass multiplied by acceleration) can be used to calculate the answer to this question.

In this case:

mass= 0.1mg= 1*10^-7 kg
velocity= 4.00*10^3 m/s
time= 6.00*10^-8 s

Using velocity and time, acceleration can be calculated as:

a= 6.667*10^10 m/s²

Substituting these values into the formula F=ma, the answer is:

F= (1*10^-7)kg * (6.667*10^10) m/s²
F= 6666.67 Newtons of force

5 0

3 years ago

A marble at the front of a truck bed traveling at 20 m/s relative to the highway rolls toward the back of the truck bed with a s

irga5000 [103]

14 m/s in the direction of the truck

5 0

3 years ago