The blocks shown in the pictures below are all made of wood. Which car will move the fastest?

A ledge on a building is 20 m above the ground. A taut rope attached to a 4.0 kg can of paint sitting on the ledge passes up ove

Andrews [41]

Answer:

t = 5.4 s

Explanation:

from the question we are given :

height (s) = 20 m

mass of paint (Mp) = 4 kg

mass of nails (Mn) = 3 kg

acceleration due to gravity (g) = 9.8 m/s^{2}

The net force accelerating the can of paint should be equal to the difference in weight of the can of paint and the can of nails.

weight of nails = mass of nails x g = 3 x 9.8 = 29.4 N

weight of paint = mass nails x g = 4 x 9.8 = 39.2 N

net force = 39.2 - 29.4 = 9.8 N

net force = total mass x acceleration

9.8 = (3 +4) x a

a = 1.4 m/s^{2}

from S = Ut + 0.5at^{2} we can get the time the carpenter has to catch the nails

where U is the initial velocity and is 0 since the can was initially at

rest

20 = (0 x t) + (0.5 x 1.4 x t^{2})

20 = 0.7 x t^{2}

t^{2} = 28.6

t = 5.4 s

8 0

3 years ago

___ energy has a slightly longer wavelength than visible light energy and can be felt to the touch

ladessa [460]

Infra-red radiation has a slightly longer wavelength than red light ...
the longest wavelength that is visible to the human eye.

Although infrared can't be detected by the eye, we do have other
receptors that CAN detect it. They are some of the nerve endings
in our skin. When infrared radiation hits these, it produces the feeling
of warmth. Infrared radiation carries heat energy.

3 0

4 years ago

20- A gram of distilled water at 4° C:

Usimov [2.4K]

Answer:

D. will decrease slightly in volume when heated to 6° C

Explanation:

6 0

3 years ago

Amy uses 20N of force to push a lawn mower 10 meters. How much work does she do? *

babunello [35]

She does 200J .

We know she uses 20N of force and 10m is the distance. We multiply both numbers and we are given our answer of 200J. Hope this was helpful. :)

4 0

4 years ago

Sphere A with mass 80 kg is located at the origin of an xy coordinate system; sphere B with mass 60 kg is located at coordinates

IRINA_888 [86]

Answer:

Fc = [ - 4.45 * 10^-8 j ] N

Explanation:

Given:-

- The masses and the position coordinates from ( 0 , 0 ) are:

Sphere A : ma = 80 kg , ( 0 , 0 )

Sphere B : ma = 60 kg , ( 0.25 , 0 )

Sphere C : ma = 0.2 kg , ra = 0.2 m , rb = 0.15

- The gravitational constant G = 6.674×10−11 m3⋅kg−1⋅s−2

Find:-

what is the gravitational force on C due to A and B?

Solution:-

- The gravitational force between spheres is given by:

F = G*m1*m2 / r^2

Where, r : The distance between two bodies (sphere).

- The vector (rac and rbc) denote the position of sphere C from spheres A and B:-

Determine the angle (α) between vectors rac and rab using cosine rule:

$cos ( \alpha ) = \frac{rab^2 + rac^2 - rbc^2}{2*rab*rac} \\\\cos ( \alpha ) = \frac{0.25^2 + 0.2^2 - 0.15^2}{2*0.25*0.2}\\\\cos ( \alpha ) = 0.8\\\\\alpha = 36.87^{\circ \:}$

Determine the angle (β) between vectors rbc and rab using cosine rule:

$cos ( \beta ) = \frac{rab^2 + rbc^2 - rac^2}{2*rab*rbc} \\\\cos ( \beta ) = \frac{0.25^2 + 0.15^2 - 0.2^2}{2*0.25*0.15}\\\\cos ( \beta ) = 0.6\\\\\beta = 53.13^{\circ \:}$

- Now determine the scalar gravitational forces due to sphere A and B on C:

Between sphere A and C:

Fac = G*ma*mc / rac^2

Fac = (6.674×10−11)*80*0.2 / 0.2^2

Fac = 2.67*10^-8 N

vector Fac = Fac* [ - cos (α) i + - sin (α) j ]

vector Fac = 2.67*10^-8* [ - cos (36.87°) i + -sin (36.87°) j ]

vector Fac = [ - 2.136 i - 1.602 j ]*10^-8 N

Between sphere B and C:

Fbc = G*mb*mc / rbc^2

Fbc = (6.674×10−11)*60*0.2 / 0.15^2

Fbc = 3.56*10^-8 N

vector Fbc = Fbc* [ cos (β) i - sin (β) j ]

vector Fbc = 3.56*10^-8* [ cos (53.13°) i - sin (53.13°) j ]

vector Fbc = [ 2.136 i - 2.848 j ]*10^-8 N

- The Net gravitational force can now be determined from vector additon of Fac and Fbc:

Fc = vector Fac + vector Fbc

Fc = [ - 2.136 i - 1.602 j ]*10^-8 + [ 2.136 i - 2.848 j ]*10^-8

Fc = [ - 4.45 * 10^-8 j ] N

3 0

4 years ago