All categories

3 years ago

What are two causes of friction

2 answers:

4 0

Answer:friction is caused by the roughness of the surface, combined with the attractive forces between the body and the surface on which it is placed. Both the things play their roles in creating the effect of friction.

alexira [117]3 years ago

3 0

Answer:

Surface roughness and deformations

Explanation:

Friction is a force that resists the relative motion between two objects or materials. The causes of this resistive force are molecular adhesion, surface roughness, and deformations. Adhesion is the molecular force resulting when two materials are brought into close contact with each other

You might be interested in

At some instant and location, the electric field associated with an electromagnetic wave in vacuum has the strength 57.5 V/m. Fi

n200080 [17]

Answer:

$1.9167\times 10^{-7}\ T$

$2.9247498849\times 10^{-8}\ J/m^3$

$8.7742496547\ W/m^2$

Explanation:

$\epsilon_0$ = Permittivity of free space = $8.85\times 10^{-12}\ F/m$

$\mu_0$ = Vacuum permeability = $4\pi \times 10^{-7}\ H/m$

E = Electric field = 57.5 V/m

c = Speed of light = $3\times 10^8\ m/s$

Magnetic field is given by

$B=\dfrac{E}{c}\\\Rightarrow B=\dfrac{57.5}{3\times 10^8}\\\Rightarrow B=1.9167\times 10^{-7}\ T$

The magnetic field strength is $1.9167\times 10^{-7}\ T$

Energy density is given by

$u=\dfrac{1}{2}\epsilon_0E^2+\dfrac{1}{2\mu_0}B^2\\\Rightarrow u=\dfrac{1}{2}\times 8.85\times 10^{-12}\times 57.5^2+\dfrac{1}{2\times 4\pi \times 10^{-7}}(1.9167\times 10^{-7})^2\\\Rightarrow u=2.9247498849\times 10^{-8}\ J/m^3$

The energy density is $2.9247498849\times 10^{-8}\ J/m^3$

Power flow per unit area is given by

$\dfrac{P}{A}=uc\\\Rightarrow \dfrac{P}{A}=2.9247498849\times 10^{-8}\times 3\times 10^8\\\Rightarrow \dfrac{P}{A}=8.7742496547\ W/m^2$

Power flow per unit area is $8.7742496547\ W/m^2$

7 0

3 years ago

A 42.5 g piece of aluminum (which has a molar heat capacity of 24.03 j/ocmol) is heated to 82.4oc and dropped into a calorimeter

Leno4ka [110]

1. Use the equation q = nC∆T
n = mols of aluminum = 42.5g/ 6.98g/mol
C = molar heat capacity = 24.03 j/Cmol
∆T = change in T from what it was before placed in calorimeter to after =
24.9C-82.4C (because water final and metal will be same temp.)
plug in to calculate q of metal =
q = (42.5/6.98)*(24.03J)(24.9-82.4)
q = -2176.5498 J
qmetal = -q of water
plug in values for water
-(-2176.5498 J) = mC∆T (m = mass of water in grams)
m = q/C∆T
∆T=24.9-22.3 C = 2.6
2176.5498 J/(2.6x4.184) = m = 200.2714 g

4 0

3 years ago

Read 2 more answers

A small boat coasts at constant speed under a bridge. A heavy sack of sand is dropped from the bridge onto the boat. The speed o

Tju [1.3M]

Answer:

d. decreases

Explanation:

The law of conservation of momentum tells us that the sum of momenta before the collision is equal to the sum of momenta after the collision. The bag has no momentum as it falls onto the boat because its velocity is zero in the horizontal direction. But after it hits the boat, it's momentum increases while the momentum of the system remains the same. That means a component of the system must decrease somewhere else. And that component is the velocity, not the mass, of the boat.

7 0

4 years ago

PLEASE HELP!

sergiy2304 [10]

Answer: b

Explanation:

p=mv

p=30

m=1500

rearrange to find v

(30)=(1500)(v)

v= 30/1500

v = 0.02 m/s

6 0

3 years ago

Việt và Thái cùng nhảy ra khỏi một chiếc be với vận tốc bằng nhau. Việt có khối lượng 75kg và nhảy về hướng đông

Lelechka [254]

Answer:

chúng hạ cánh cùng một lúc.

Explanation:

5 0

3 years ago