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3 years ago

Why does a stop sign appear red?

Physics

1 answer:

dolphi86 [110]3 years ago

8 0

Answer:

because it’s suppose to be red like a stop light.

Explanation:

So it tells you to stop

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A rocket ship starts from rest and turns on its forward booster rockets, causing it to have a constant acceleration of 4 \,\dfra

Sergio039 [100]

Answer:

+12 m/s

Explanation:

The velocity of an object moving of accelerated motion is given by:

$v(t) = v_0 +at$

where

v0 is the initial velocity of the object

a is the acceleration

t is the time

In this problem, the rocket starts from rest, so $v_0 =0$ . The acceleration is $a=4 m/s^2$ , so the velocity after $t=3 s$ will be

$v(3 s)=0 +(4 m/s^2)(3 s)=+12 m/s$

6 0

3 years ago

A playground is on the flat roof of a city school, 6.2m above the street below. The vertical wall of the building is h=7.30m hig

olya-2409 [2.1K]

Answer:

a. 18.13m/s

b. 0.84m

c. 2.4m

Explanation:

a. to find the speed at which the ball was lunched, we use the horizontal component.Since the point distance from the base of the ball is 24m and it takes 2.20 secs to reach the wall,we can say that

t=distance /speed

$speed v_{x}=vcos\alpha=24/2.2=10.9m/s\\V=10.9/cos53^{0}\\V=18.13m/s$

Hence the speed at which ball was lunched is 18.13m/s

b. from the equation

$y=v_{y}t-\frac{1}{2}gt^{2}\\ v_{y}=18.13sin53=14.48m/s\\\\y=(14.48*2.2)-\frac{1}{2}9.8*2.2^{2}\\y=8.14m\\$

the vertical distance at which the ball clears the wall is

y=8.14-7.3=0.84m

c. the time it takes the ball to reach the 6.2m vertically

$6.2=14.47t-4.8t^{2}\\\\14.47t-4.8t^{2}-6.2=0\\\using\\t=-b±\frac{\sqrt{b^{2}-4ac} }{2a}\\ where \\a=-4.8, b=14.47t, c=6.2\\hence t=2.4secs$

the horizontal distance covered at this speed is

$y+24=(18.13cos53)2.4\\y=26.186-24\\y=2.12m$

4 0

3 years ago

Calculate the average velocity of a car that travels 555 km north east in 3.7 hours

Vera_Pavlovna [14]

Your answer:

150 kilometer's per hour.

7 0

3 years ago

A car starts from rest at a stop light and reaches 20m/s in 3.5s. Determine the acceleration of the car

olga55 [171]

The car accelerated at around ~5.7 m/s

8 0

3 years ago

I'm studying the equilibrium of forces so hard that I got confused for a sec. Is the force due to gravity included in summing up

jenyasd209 [6]

Answer:

Yes, you would consider the mass × gravity at the centre of gravity of the object in question to cause a moment, hence it should be included in your resolution

3 0

2 years ago