Calculate the velocity of a 80kg man that has a momentum of 720 kg m/s

An 75-kg hiker climbs to the summit of Mount Mitchell in western North Carolina. During one 2.0-h period, the climber's vertical

Ostrovityanka [42]

Answer:

The change in gravitational potential energy of the climber-Earth system is $\Delta PE = 396900 \ J$

Explanation:

From the question we are told that

The mass of the hiker is $m = 75 \ kg$

The time taken is $T = 2 \ hr = 2 * 3600 = 7200 \ s$

The vertical elevation after time T is $H = 540 \ m$

The change in gravitational potential is mathematically represented as

$\Delta PE = mgH$

here g is the acceleration due to gravity with value $g = 9.8 \ m/s^2$

substituting values

$\Delta PE = 75 * 9.8 * 540$

$\Delta PE = 396900 \ J$

3 0

3 years ago

Which statements best describe half-lives of radioactive isotopes? Check all that apply.

victus00 [196]

Answer:

A

Explanation:

half life is the time taken for a radioactive isotopes to dissociate

7 0

2 years ago

A square plate of side 9 m is submerged in water at an incline of 60∘ with the horizontal. Its top edge is located at the surfac

Tpy6a [65]

Answer:

The force on one side of the plate is 3093529.3 N.

Explanation:

Given that,

Side of square plate = 9 m

Angle = 60°

Water weight density = 9800 N/m³

Length of small strip is

$y=\dfrac{\Delta y}{\sin60}$

$y=\dfrac{2\Delta y}{\sqrt{3}}$

The area of strip is

$dA=\dfrac{9\times2\Delta y}{\sqrt{3}}$

We need to calculate the force on one side of the plate

Using formula of pressure

$P=\dfrac{dF}{dA}$

$dF=P\times dA$

On integrating

$\int{dF}=\int_{0}^{9\sin60}{\rho g\times y\times 6\sqrt{3}dy}$

$F=9800\times6\sqrt{3}(\dfrac{y^2}{2})_{0}^{9\sin60}$

$F=9800\times6\sqrt{3}\times(\dfrac{(9\sin60)^2}{2})$

$F=3093529.3\ N$

Hence, The force on one side of the plate is 3093529.3 N.

7 0

3 years ago

If the work done to stretch an ideal spring by 4.0 cm is 6.0J, what is the spring constant (force constant) of this spring?

cluponka [151]

As AL2006 correctly pointed out the formula is 1/2 kx^2. I was thinking of force and work is the integral of force over the distance applied. So now
$W= \frac{1}{2}k x^{2}$
and
$\frac{2*6.0}{0.04^{2} } = k =7500 \frac{J}{m^{2}}$

8 0

3 years ago

Read 2 more answers

Give Example of mental flexibility

Inessa [10]

Answer:

If you ring the doorbell and no one opens the door, you'll infer that no one is home rather than continuing to ring the doorbell to an empty house. Being able to understand this and look for another solution is another example of mental flexibility.

Explanation:

6 0

3 years ago