The attractive force that acts between all objects is the (5 points)

8.)The potential energy of a 40-kg cannonball is 14000 J. How high was the cannon ball to have this much potential energy?

Delvig [45]

Hey! I empathize with you, as I just started the energy unit in physics as well!

Alright, lets list what we know, and which equation(s) we need.

PE = Gravitational Potential Energy

$PEg = mgh$

m = mass

g = gravity (9.8 m/s^2)

h = height

Guess what?

We need to find the height!

Lets make this more organized:

Known:

m = 40 kg

PE = 14000

g = 9.8 m/s^2

Unknown:

h = ?

================================

Now, if we take a look at the equation PEg = mgh, you will see that we have everything besides the height! So lets solve for the height by substituting in for the variables we know:

14000 J = 40 kg * (9.8 m/s^2) * h

40 * 9.8 = 392

14000 J = 392 * h

14000/392 = h

35.71 m = h

There we go! If you simply list what you know and don't know, you will find the equation you need to solve the problem.

Have a great day and good luck!

7 0

2 years ago

There is a limit to how long your neck can be. If your neck were too long, no blood would reach your brain! What is the maximum

spayn [35]

Answer:

The maximum height a person's brain could be above his heart is: 1.28 meter.

Explanation:

We need to know what is the normal blood pressure ours hearts so there is a rate: 120/80 (mmHg) and the average will be: 100 (mmHg) and using the Pascal law that relate pressure, density, gravity and height like: $P_{2} = pgh_{1} - pgh_{2} + P_{1}$ , where P is pressure, p is density, g is the gravity acceleration and h is the height. Now we can find the height and delta of pressure will be: P2-P1 = 100 (mmHg), knowing that 1(mmHg) is equal to 133 Pa, we can do the convertion to 13332.2 (Pa), now because the units of Pascal are Newton/(meter^2). Then we solve the formula to get the height: $\frac{P2-P1}{pg} =h$ so we get: $\frac{13332.2}{(1060*9,81)}=Height=1.28(meters).$