What heat transfer are uv rays from the sun. Radiation, conduction, or convection

A box of books weighing 290 N is shoved across the floor of an apartment by a force of 400 N exerted downward at an angle of 34.

NARA [144]

Answer: 1.95s

Explanation:

Given

ma = 290 cos 34.9 - fk

fk = 290 cos 34.9 - ma

fn = mg + 400 sin Φ

fn = 290 + 400 sin 34.9

fn = 290 + 228.9

fn = 518.9

fk = fn * uk

uk = 0.57

290 cos 34.9 - ma = 518.9 * 0.57

290 cos 34.9 - ma = 295.8

290 cos 34.9 - 295.8 = ma

ma = -58

m = 290/10 = 29

a = 58/29

a = 2

Using equation of motion

S = ut + .5at²

3.8 = 0 + .5*2*t²

3.8 = t²

t = 1.95s

3 0

3 years ago

A spherical mirror gives an image magnified 5 times at a distance 5 m. determine whether the mirror is convex or concave? How mu

irakobra [83]

Answer:

1. Concave mirror.

2. 4.17 m or 417 cm.

Explanation:

The following data were obtained from the question:

Object distance (u) = 5 m

Magnification (M) = 5

Focal length (f) =..?

1. Identification of the mirror.

To determine whether or not the mirror is concave or convex, we must first of all calculate the image distance.

This can be obtained as follow:

Object distance (u) = 5 m

Magnification (M) = 5

Image distance (v) =.?

Magnification (M) = image distance (v) /object distance (u).

M = v/u

5 = v/5

Cross multiply

v = 5 x 5

v = 25 m

Since the image distance obtained is positive, the mirror is said to be a concave mirror.

2. Determination of the focal length of the mirro.

This can be obtained as follow:

Object distance (u) = 5 m

Image distance (v) = 25 m

Focal length (f) =...?

1/f = 1/v + 1/u

1/f = 1/25 + 1/5

1/f = 0.04 + 0.2

1/f = 0.24

Cross multiply

f x 0.24 = 1

Divide both side by 0.24

f = 1/0.24

f = 4.17 m

Converting the focal length of cm, we have:

1 m = 100 cm

Therefore, 4.17 m = 4.17 x 100 = 417 cm

Therefore, the focal length of the mirror is 4.17 or 417 cm.

4 0

3 years ago

Imagine two people , each seating on an office chair with wheels. One pushes against the other Describe what happen next Explain

zaharov [31]

Answer:

The two chairs and those sitting on them will move in nearly opposite directions at almost the same speed (assuming that the wheels can only move into two directions - front or back and assuming that the weight of both people are almost the same)

Explanation:

Newton's Third Law states that If an object X exerts a force on object Y, then object Y must exert a force of equal magnitude and opposite direction back on object X.

In other words, when force is applied from source A at B and in direction of B, B also simultaneously returns the force on B and in the direction of B.

This law applies when we jump off the ground when a rocket takes off from the earth into space, etc.

While standing, the body pushes on the earth with a force equal to its own weight. If the ground underneath the body does not meet that force in an equal and opposite direction, both standing on the earth will fall into the earth, with the earth caving underneath it.

You can see why it is important to have a strong foundation for a building and why the depth and strength of the foundation will depend on how much weight is going on it.

Cheers!

3 0

3 years ago

Give four importantnce of recycling

Crank

Answer:

prevents pollution, reduces the need to harvest new raw materials, saves energy, reduce greenhouse gas

8 0

3 years ago

Read 2 more answers

what would be more damaging:having a head-on collision with an identical car at the same speed or driving head on into a crash b

natali 33 [55]

A head on collision would be worse and it would actually be four times as worse since the speed is doubled and energy is a squared value so by far a head on collision with another car

4 0

3 years ago