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3 years ago

What does a black asphalt road become hotter than a white cement sidewalk in the same amount of sunlight?

1 answer:

7 0

The black means that it is a great emitter/absorber of the electromagnetic spectrum. The electromagnetic radiation is reflected of the white and absorbed nurture black meaning that the temperature of the black tarmac increases to that greater the the white

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A ball is kicked from the top of a building with a velocity of 50 m/s and lands 165 m away from the base of the building.

Nadusha1986 [10]

The height of the building is 53.4 m (projectile motion)

Explanation:

The motion of the ball is a projectile motion, so it follows a parabolic path which consists of two independent motions:

- A uniform motion (constant velocity) along the horizontal direction

- An accelerated motion with constant acceleration (acceleration of gravity) in the vertical direction

First of all, we consider the horizontal motion, which is a uniform motion at constant speed. The equation that gives the horizontal distance travelled is:

$d=v_x t$

where:

$v_x = 50 m/s$ is the horizontal velocity of the ball, which is constant since there are no forces in this direction

d = 165 m is the horizontal distance travelled by the ball

Solving for t, we find the time of flight:

$t=\frac{d}{v_x}=\frac{165}{50}=3.3 s$

Now we analyze the vertical motion: it is an accelerated motion, we can use the suvat equation

$s=ut+\frac{1}{2}at^2$

where

s is the vertical displacement, which is the height of the building

u = 0 is the initial vertical velocity of the ball

t = 3.3 s is the time of flight

$a=g=9.8 m/s^2$ is the acceleration of gravity

Solving for s, we find the height of the building:

$s=0+\frac{1}{2}(9.8)(3.3)^2=53.4 m$

Learn more about projectile motion here:

brainly.com/question/8751410

#LearnwithBrainly

6 0

4 years ago

Satellites, A and B, each of mass m, are to be launched into circular orbits about Earth's center. Satellite A is to orbit at an

Volgvan

Answer:

0.63

Explanation:

We are given that

Radius of earth, $R_E=6370 km$

Radius of orbit A, $R_A=7590+6370=13960 km$

Radius of orbit B, $R_B=6370+15800=22170 km$

We have to find the ratio of the potential energy of satellite B to that of satellite A in orbit.

Potential energy of orbit A= $U_A=-\frac{GM}{R_A}=-\frac{GM}{13960}$

Potential energy of orbit B= $U_B=-\frac{GM}{R_B}=-\frac{GM}{22170}$

$\frac{U_B}{U_A}=\frac{13960}{22170}=0.63$

Hence,the ratio of the potential energy of satellite B to that of satellite A in orbit=0.63

8 0

4 years ago

If time is tripled and work remains the same the power will.

VMariaS [17]

Answer:

power will three times decrease (one-third)

Explanation:

P = W / t

thus when work is constant, power is inversely proportional to time

so, when time is tripled, power is decreased to one-third

7 0

3 years ago

Two trains approach each other on parallel tracks. Each has a speed of 95 kph relative to the ground. If they are initially 8.5

aliya0001 [1]

Answer: 2.83 minutes

Explanation:

It is understood that trains are approaching. That is, they have speeds of equal magnitude but opposite. When train A travels x meters northbound, then train B travels the same distance southbound.

Therefore trains approach at a speed of:

$V = 95 +95 = 190\ km / h$