3 years ago

Question 9 of 20

1 answer:

5 0

B, we can use a power drill for an example, the motars are used by electricity (electrical energy) and used to screw in wood (mechanical energy)

You might be interested in

A 0.25 kg ball is suspended from a light 0.65 m string as shown. The string makes an angle of 31° with the vertical. Let U = 0 w

steposvetlana [31]

Explanation:

a) The height of the ball h with respect to the reference line is

$h = L - L\cos{31°} = L(1 - \cos{31°})$

so its initial gravitational potential energy $U_0$ is

$U = mgh = mgL(1 - \cos{31°})$

$\:\:\:\:\:=(0.25\:\text{kg})(9.8\:\text{m/s}^2)(0.65\:\text{m})(1 - \cos{31})$

$\:\:\:\:\:=0.23\:\text{J}$

b) To find the speed of the ball at the reference point, let's use the conservation law of energy:

$\Delta{K} + \Delta{U} = 0 \Rightarrow K_0 + U_0 = K + U$

We know that the initial kinetic energy $K_0,$ as well as its final gravitational potential energy $U$ are zero so we can write the conservation law as

$mgL(1 - \cos{31°}) = \frac{1}{2}mv^2$

Note that the mass gets cancelled out and then we solve for the velocity v as

$v = \sqrt{2gL(1 - \cos{31°})}$

$\:\:\:\:\:= \sqrt{2(9.8\:\text{m/s}^2)(0.65\:\text{m})(1 - \cos{31°})}$

$\:\:\:\:\:= 1.3\:\text{m/s}$

5 0

3 years ago

Read 2 more answers

a stockbroker "talks up" a piece of stock that he wants you to buy because it was a high return rate. This is an example of: ?

kozerog [31]

I believe the answer is manipulation of information. Hope I helped!

8 0

3 years ago

Read 2 more answers

How much potential energy does a 1kg mess have 10m off the ground?

777dan777 [17]

Potential Energy = mass x gravitational acceleration x height
potential Energy = 1 x 9.8 x 10 = 98 joules

3 0

3 years ago

An airplane changes its velocity uniformly from 150 m/s to 60 m/s in 15 s. Calculate:

Arlecino [84]

Answer:2.5

Explanation:

7 0

3 years ago

Does parallax affect the precision of a measurement that you make

Paul [167]

Yes, parallax affects the precision of a measurement that you make. It introduces an error in the order of the parallax. It will cause the measurement to be different from the real answer. Hope this answers the question. Have a nice day.

8 0

4 years ago

Read 2 more answers