Ask question

Ask question

All categories

3 years ago

14

A book rests on a table. The earth pulls down on the book through the weight force. Which force is the reaction force to the wei

ght force?
1. the force of the Earth on the book
2. the force on the table on the book
3. the force of the Earth on the table
4. the force of the book on the Earth
5. the inertia of the book

1 answer:

Veseljchak [2.6K]3 years ago

7 0

Newton's 3rd law: The force that A exerts on B is equal and opposite (in direction) to the force that B exerts on A.

Substitute the words "the earth" for A and "the book" for B.

You might be interested in

Which of these is an effect of gravity?

castortr0y [4]

Answer:

(A)

A cup placed on a table won't float away

3 0

3 years ago

A 250 kg crate is placed on an adjustable inclined plane. If the crate slides down the incline with an acceleration of 0.7 m/s2

stepladder [879]

Answer:

21.2 degrees

Explanation:

Let gravitational acceleration constant g = 9.81 m/s2 directed downward. We can calculate the g component that is parallel to the 25 degree incline:

$gsin25^0 = 9.81sin25^0 = 4.15 m/s^2$

This parallel component would produce an acceleration of the block. But since the net acceleration is only 0.7 m/s2, there's a friction acceleration that hinders g parallel. This acceleration can be calculated by

$4.15 - a_f = a = 0.7$

$a_f = 4.15 - 0.7 = 3.45 m/s^2$

The force of friction would be

$F_f = a_fm = 250 * 3.45 = 816.5 N$

Friction is a product of normal force and its coefficient

$F_f = \mu N = \mu mgcos25^0 = \mu 250*9.81*cos25^0 = 2222.72 \mu$

$\mu = F / 2222.72 = 816.5 / 2222.72 = 0.388$

For the crate to slide down at constant speed, the net acceleration must be 0. In other words, the parallel g must be the same as acceleration caused by friction. Let this incline angle be α

$g sin\alpha = a_f = F_f/m = \frac{\mu N}{m} = \frac{\mu mgcos\alpha}{m} = \mu g cos\alpha$

$sin\alpha = \mu cos\alpha$

$\frac{sin \alpha}{cos \alpha} = \mu$

$tan\alpha = \mu = 0.388$

$\alpha = tan^{-1} 0.388 = 0.37 rad = 0.37*180/\pi \approx 21.2^0$

6 0

4 years ago

The earth orbits the sun once per year at the distance of 1.50 x 1011 m. Venus orbits the sun at a distance of 1.08 x 1011 m. Th

worty [1.4K]

Answer:

Venus will take 223.015 days to make one orbit around the sun .

Explanation:

Given that,

Distance $r = 1.50\times10^{11}\ m$

Distance $r'=1.08\times10^{11}\ m$

We need to calculate the time period for Venus

Using Kepler's third law

For Earth,

$T^2\propto r^3$ ....(I)

For Venus,

$T'^2\propto r'^3$ ....(II)

Ratio of equation (I) and (II)

$\dfrac{T'^2}{T^2}=\dfrac{r'^3}{r^3}$ ....(I)

Put the value in the equation

$\dfrac{T'^2}{T^2}= \dfrac{1.08\times10^{11}}{1.50\times10^{11}}$

$T'^2=\dfrac{1.08\times10^{11}}{1.50\times10^{11}}\timesT^2$

$T'^2=(\dfrac{1.08\times10^{11}}{1.50\times10^{11}})^{\dfrac{3}{2}}\times1$

$T=0.6109\ earth year$

$T=0.611\times365$

$T=223.015\ days$

Hence, Venus will take 223.015 days to make one orbit around the sun

8 0

3 years ago

What part of the electromagnetic spectrum can cause sunburn? radio waves infrared light gamma rays ultraviolet light

padilas [110]

It is the Ultra violet light

7 0

3 years ago

Read 2 more answers

A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughin

Dahasolnce [82]

Answer:

2100 J

Explanation:

Work = force × distance

W = Fd

W = (140 N) (15 m)

W = 2100 J

3 0

4 years ago

Read 2 more answers