All categories

3 years ago

What is a good example of a contact force?

Physics

1 answer:

exis [7]3 years ago

5 0

Answer:

Sitting on a couch

Explanation:

The couch is exerting an upwards force so that would make it a contact force

You might be interested in

A rugby player runs with the ball directly toward his opponent's goal, along the positive direction of an x axis. He can legally

Katyanochek1 [597]

Answer:125.68°

Explanation:

6 0

3 years ago

A copper cable needs to carry a current of 160 A with a power loss of only 2.0 W/m. What is the required radius of the copper ca

lesantik [10]

Answer:

The radius of the cable is 0.0083 m or 8.3 mm.

Explanation:

The resistance of copper cable of 1 meter length will be given by

$R_{cable} = \frac{\rho \times l}{a}$ .... (i)

where the resistivity of copper is $\rho = 1.7 \times 10^{-8} \Omega.m$ , and l is the length of the wire which is considered to be 1m, and a is the cross sectional area of the wire in $m^{2}$ .

From the formula of power we know that, $P = I^2 R$ .... (ii)

Therefore 2 W/m = $(160)^2 \times R$ .... (iii)

where the resistance,R, actually means the resistance of the cable per meter.

Therefore R ( resistance of cable per meter)

= $\frac{2}{160^2} = 7.812 \times 10^{-5}$ ohms / meter. .... (iv)

Therefore from (i)

$7.812 \times 10^{-5}$ = $\frac{1.7 \times 10^{-8} \times 1}{a} = \frac{1.7 \times 10^{-8} \times 1}{\pi r^{2} }$ ..... (v)

where cross sectional area of the cable, a = $\pi r^2$ ,

where r is the radius of the cable, and length of cable,l = 1m.

Therefore r = $\sqrt{\frac{ 1.7 \times 10^{-8}}{\pi \times 7.812 \times 10^{-5} } } = 0.0083m = 8.3 mm$

5 0

3 years ago

Recall that impulse = momentum (FAt = Ap and that Ap is just mx v). How long (time) must a group of people pull with a force of

elixir [45]

The time taken for the group of people to pull the car, giving it a velocity of 1.5 m/s is 3.75 s

Momentum is simply defined as the product of mass and velocity i.e

Momentum = mass × velocity

To answer the question given, we'll begin by calculating the change in momentum. This can be obtained as follow:

Mass = 1500 Kg

Initial velocity (u) = 0 m/s

Final velocity (v) = 1.5 m/s

<h3>Change in momentum =? </h3>

Change in momentum = m(v – u)

Change in momentum = 1500 (1.5 – 0)

Change in momentum = 1500 × 1.5

<h3>Change in momentum = 2250 Kg•m/s</h3>

Finally, we shall determine the time

Change in momentum = 2250 Kg•m/s

Force (F) = 600 N

Impulse = Ft = change in momentum

FT = change in momentum

600 × t = 2250

Divide both side by 600

t = 2250 / 600

Thus, the time required is 3.75 s

Learn more on momentum and impulse: brainly.com/question/14486244

6 0

2 years ago

Help me with questions 1-8. here's the link to the textbook

SVETLANKA909090 [29]

Ok so basically I’m here for the points cuz I gotta quiz do in 10 minutes sorry

5 0

3 years ago

If the magnetic field of an electromagnetic wave is in the +x-direction and the electric field of the wave is in the +y directio

alexandr1967 [171]

Answer:

Explanation:

The direction of propagation of electromagnetic wave

is given by the direction of vector E x B where E is electrical field , B is magnetic field .

Given Electric field = E i because it is along x axis

Magnetic field = Bj because it is along y axis

E x B = Ei x Bj

= EB k .

so direction of E x B is along k direction or z - axis so wave is propagating along z - axis .

7 0

2 years ago