Which one gives the feeling of heaviness in the case of a kilogram of cotton or a kilogram of lead? Why?

Physics

1 answer:

brilliants [131]3 years ago

3 0

Strange as it may seem, they both give the same "feeling of heaviness".

If you put them in a pair of equal-size sealed boxes, there's no way for anyone to tell which box has the cotton and which box has the lead.

You might be interested in

If a weight hanging on a string of length 5 feet swings through 5^\circ on either side of the vertical, how long is the arc thro

Zielflug [23.3K]

<span>First we can find the circumference of the whole circle with a radius of 5 feet. circumference = 2 pi radius circumference = (2 pi) (5 feet) circumference = (10 pi) feet From one high point to the other high point, the string moves through an angle of 10 degrees. Since a full circle is 360 degrees, this angle is 1/36 of a full circle. Therefore, the arc length is 1/36 of the whole circumference. arc length = (1/36) (circumference) arc length = (1/36) (10 pi) feet arc length = 0.873 feet</span>

7 0

3 years ago

A 1400 kg car starts from rest on a horizontal road and gains a speed of 61 km/h in 19 s. (a) what is its kinetic energy at the

lana [24]

(a) Let's convert the final speed of the car in m/s:
$v_f = 61 km/h = 16.9 m/s$
The kinetic energy of the car at t=19 s is
$K= \frac{1}{2}mv_f^2= \frac{1}{2}(1400 kg)(16.9 m/s)^2=2.00 \cdot 10^5 J$

(b) The average power delivered by the engine of the car during the 19 s is equal to the work done by the engine divided by the time interval:
$P= \frac{W}{\Delta t}$
But the work done is equal to the increase in kinetic energy of the car, and since its initial kinetic energy is zero (because the car starts from rest), this translates into
$P= \frac{K}{\Delta t}= \frac{2.00 \cdot 10^5 J}{19 s}=1.05 \cdot 10^4 W$

(c) The instantaneous power is given by
$P_i = Fv_f$
where F is the force exerted by the engine, equal to F=ma.

So we need to find the acceleration first:
$a= \frac{v_f-v_i}{\Delta t}= \frac{16.9 m/s}{19 s}=0.89 m/s^2$
And the problem says this acceleration is constant during the motion, so now we can calculate the instantaneous power at t=19 s:
$P_i = Fv=(ma)v=(1400 kg)(0.89 m/s^2)(16.9 m/s)=2.11 \cdot 10^4 W$

5 0

3 years ago

A ball is let go and falls to the ground. It bounces a few times before

Ksenya-84 [330]

Answer:

I just want the points but you should pay attention in class jk

4 0

3 years ago

15. Some people have observed that animal behavior changes just before an earthquake. What might explain this?

Ber [7]

Answer:

15: Animals are able to detect the first of an earthquake's seismic waves—the P-wave, or pressure wave, that arrives in advance of the S-wave, or secondary, shaking wave. This likely explains why animals have been seen snapping to attention, acting confused or running right before the ground starts to shake.

16: No, it is not even remotely true. Microwaves cook food from the outside in, just like a regular oven. In fact, most of the cooking on the inside of the food, depending on its thickness, is done by heat conduction from the outside surfaces inwards, as the microwaves do not actually penetrate that far into the food.

3 0

2 years ago

A box of mass 50 kg is pushed hard enough to set it in motion across a flat surface. Then a 99-N pushing force is needed to keep

vitfil [10]

Answer:

0.20

Explanation:

The box is moving at constant velocity, which means that its acceleration is zero; so, the net force acting on the box is zero as well.

There are two forces acting in the horizontal direction:

- The pushing force: F = 99 N, forward

- The frictional force: $F_f=\mu mg$ , backward, with