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3 years ago

17. Which of the following is the closest weight in newtons of a 7.0-kilogram

Physics

1 answer:

marusya05 [52]3 years ago

4 0

Weight = (mass) x (gravity)

Weight = (7.0 kg) x (gravity)

On Earth, where (gravity) is roughly 10 N/kg . . .

Weight = (7.0 kg) x (roughly 10 N/kg)

Weight = roughly 70 Newtons

That's B on Earth.

It would be some other number on other bodies.

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A 60 kg person sits in a chair. How much does the earth pull on the person? (Acceleration due to gravity is -10m/s2) F = mxa → F

MA_775_DIABLO [31]

Answer:

600N(downwards)

Explanations

600N(downwards)

Mas of the person = 60kg

Acceleration due to gravity = -10m/s²

To get the earths pull on the person, we will use the Newton second law of motion;

Force = mass * acceleration;

Force = 60 * -10

Force- -600N

Hence the earth gravitational pull on the person is 600N(downwards). It is downwards due to the negative sign.

7 0

2 years ago

Which best describes internet wikis as a source of scientific information

scoundrel [369]

Answer:

They are written or edited by anyone

Explanation:

5 0

3 years ago

3. A football is kicked with a speed of 35 m/s at an angle of 40°.

jarptica [38.1K]

a) 22.5 m/s

The initial vertical velocity is given by:

$u_y = u sin \theta$

where

u = 35 m/s is the initial speed

$\theta=40^{\circ}$ is the angle of projection of the ball

Substituting into the equation, we find

$u_y = (35)(sin 40)=22.5 m/s$

b) 26.8 m/s

The initial horizontal velocity is given by:

$u_x = u cos \theta$

where

u = 35 m/s is the initial speed

$\theta=40^{\circ}$ is the angle of projection of the ball

Substituting into the equation, we find

$u_x = (35)(cos 40)=26.8 m/s$

c) 2.30 s

The time it takes for the ball to reach the maximum heigth can be found by considering the vertical motion only. This is a uniformly accelerated motion (free-fall), so we can use the suvat equation

$v_y = u_y + at$

where

$v_y$ is the vertical velocity at time t

$u_y = 22.5 m/s$

$a=g=-9.8 m/s^2$ is the acceleration of gravity (negative because it is downward)

At the maximum height, the vertical velocity becomes zero, $v_y =0$ ; substituting, we find the time t at which this happens:

$0=u_y + gt\\t=-\frac{u_y}{g}=-\frac{22.5}{-9.8}=2.30 s$

d) 25.8 m

The maximum height can also be found by considering the vertical motion only. We can use the following suvat equation:

$s=u_y t + \frac{1}{2}gt^2$

where

s is the vertical displacement at time t

$u_y = 22.5 m/s$

$g=-9.8 m/s^2$

Substituting t = 2.30 s, we find the displacement at maximum height, so the maximum height:

$s=(22.5)(2.30)+\frac{1}{2}(-9.8)(2.30)^2=25.8 m$

e) 123.3 m

In order to find how far does the ball lands, we have to consider the horizontal motion.

First of all, the time it takes for the ball to go back to the ground is twice the time needed for reaching the maximum height:

$t=2(2.30 s)=4.60 s$

Then, we consider the horizontal motion. There is no acceleration along this direction, so the horizontal velocity is constant:

$v_x = 26.8 m/s$

Therefore, the horizontal distance travelled during the whole motion is

$d=v_x t = (26.8)(4.60)=123.3 m$

So, the ball lands 123.3 m far from the initial point.

4 0

3 years ago

1. A man travels 45 m in 35 seconds. How fast is that? What’s the answer

Natalija [7]

Answer:

1.28

Explanation:

If you want to find the m/s you would divide distance by time, so

45 divided by 35 would equal 1.28571429 and so on.

you can just write the three first numbers.

8 0

3 years ago

The distance between slits in a double-slit experiment is decreased by a factor of 2. If the distance between fringes is small c

Elodia [21]

Answer:

the distance between adjacent fringes is increased by a factor o 2

Explanation:

To find how the distance between fringes is modified you can use the following formula for the calculation of the distance between fringes:

$\Delta y=\frac{\lambda D}{d}$

D: distance to the screen

d: distance between slits

λ: wavelength of the light

if d is decreased by a factor of 2, that is d'=1/2d, you have:

$\Delta y'=\frac{\lambda D}{d'}=\frac{\lambda D}{(1/2)d}=2\Delta y$

hence, the distance between adjacent fringes is increased by a factor o 2

4 0

3 years ago