1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
creativ13 [48]
3 years ago
6

What changes a ball velocity

Physics
1 answer:
Grace [21]3 years ago
5 0

Answer/Explanation: Speed and direction can change with time. When you throw a ball into the air, it leaves your hand at a certain speed. As the ball rises, it slows down. Then, as the ball falls back toward the ground, it speeds up again. When the ball hits the ground, its direction of motion changes and it bounces back up into the air.

You might be interested in
How can you keep sound out of a room
GREYUIT [131]
To keep<span> noise from entering your space, look for </span>sound<span> blockers</span>
8 0
3 years ago
Lasers are classified according to the eye-damage danger they pose. Class 2 lasers, including many laser pointers, produce visib
Alexus [3.1K]

Answer:

<em>a) 318.2 W/m^2</em>

<em>b) 2.5 x 10^-4 J</em>

<em>c) 1.55 x 10^-8 v/m</em>

<em></em>

Explanation:

Power of laser P = 1 mW = 1 x 10^-3 W

exposure time t = 250 ms = 250 x 10^-3 s

If beam diameter = 2 mm = 2 x 10^-3 m

then

cross-sectional area of beam A = \pi d^{2} /4 = (3.142 x (2*10^{-3} )^{2})/4

A = 3.142 x 10^-6 m^2

a) Intensity I = P/A

where P is the power of the laser

A is the cros-sectional area of the beam

I = ( 1 x 10^-3)/(3.142 x 10^-6) = <em>318.2 W/m^2</em>

<em></em>

b) Total energy delivered E = Pt

where P is the power of the beam

t is the exposure time

E = 1 x 10^-3 x 250 x 10^-3 = <em>2.5 x 10^-4 J</em>

<em></em>

c) The peak electric field is given as

E = \sqrt{2I/ce_{0} }

where I is the intensity of the beam

E is the electric field

c is the speed of light = 3 x 10^8 m/s

e_{0} = 8.85 x 10^9 m kg s^-2 A^-2

E = \sqrt{2*318.2/3*10^8*8.85*10^9}  = <em>1.55 x 10^-8 v/m</em>

6 0
3 years ago
You are working as an assistant to an air-traffic controller at the local airport, from which small airplanes take off and land.
Alika [10]

Answer:

d = 2021.6 km

Explanation:

We can solve this distance exercise with vectors, the easiest method s to find the components of the position of each plane and then use the Pythagorean theorem to find distance between them

Airplane 1

Height   y₁ = 800m

Angle θ = 25°

           cos 25 = x / r

           sin 25 = z / r

           x₁ = r cos 20

           z₁ = r sin 25

          x₁ = 18 103 cos 25 = 16,314 103 m = 16314 m

          z₁ = 18 103 sin 25 = 7,607 103 m= 7607 m

2 plane

Height   y₂ = 1100 m

Angle θ = 20°

          x₂ = 20 103 cos 25 = 18.126 103 m = 18126 m

          z₂ = 20 103 without 25 = 8.452 103 m = 8452 m

The distance between the planes using the Pythagorean Theorem is

         d² = (x₂-x₁)² + (y₂-y₁)² + (z₂-z₁)²2

Let's calculate

        d² = (18126-16314)²  + (1100-800)² + (8452-7607)²

        d² = 3,283 106 +9 104 + 7,140 105

        d² = (328.3 + 9 + 71.40) 10⁴

        d = √(408.7 10⁴)

        d = 20,216 10² m

        d = 2021.6 km

7 0
3 years ago
Plzz Help easy quesion for 20 points Why does someone get burned if they touch an old filament bulb that has been on for a few h
fgiga [73]
Incandescent lights get hot very quickly and therefore can easily burn u or catch fire
5 0
3 years ago
Read 2 more answers
What is the speed of an 800 kg automobile if it has a kinetic energy of 9.00 x 10^J?
MA_775_DIABLO [31]

Ek = 1/2 mv^2

9 × 10^4 = 1/2 × 800 × v^2

9 × 10^4/400 = 400 v^2 / 400

9 × 10^4/400 = v^2

√225 = v

15 ms⁻¹ = v

That's the only way I know how to work it out

I think in this case velocity and speed would be considered the same because me

s = d/t and v=d/t

one is distance travelled and the other is displacement of a body

7 0
2 years ago
Other questions:
  • Which of the following has both kinetic and potential energy?
    11·1 answer
  • Which of the following is not found in the nucleus of an atom?
    12·2 answers
  • (a) calculate the height of a cliff if it takes 2.35 s for a rock to hit the ground when it is thrown straight up from the cliff
    13·1 answer
  • Sound waves need a ___________ for the vibrations to travel and they move in the pattern of a ______________ wave.
    7·1 answer
  • WHY ADIABAT IS STEEPER THAN ISOTHERM???
    6·1 answer
  • . An L-R-C series circuit has C = 4.80 mF, L = 0.520 H, and source voltage amplitude V = 56.0 V. The source is operated at the r
    9·1 answer
  • Under some circumstances, a star can collapse into an extremely dense object made mostly of neutrons and called a neutron star.
    8·1 answer
  • Stress is a factor that contributes to heart disease risk.true or false
    12·1 answer
  • Ulesr...<br> 4.What makes the molecular shape of Co, and NH, different? (2 points)<br> luence.
    7·1 answer
  • 21. A person standing 49.5m from the foot of a cliff claps his hands and hears an echo 0.3
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!