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diamong [38]
3 years ago
12

What are two ways friction can be useful

Physics
1 answer:
Mnenie [13.5K]3 years ago
4 0
Gravity is an example of friction.  If we didn't have gravity, we would be flying all over the place.  Also, friction keeps us from sliding on the ground and falling.
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1. Calculate the density of a 5.00 g marble which, when placed in a
gregori [183]

Answer:

1. 0.625 g/mL

2. 2×10⁵ J

3. 5040 J

4. 75000 J

Explanation:

1. Determination of the density.

We'll begin by calculating the volume of the marble. This can be obtained as follow:

Volume of water = 60 mL

Volume of water + Marble = 68 mL

Volume of marble =?

Volume of marble = (Volume of water + Marble) – (Volume of water)

Volume of marble = 68 – 60

Volume of marble = 8 mL

Finally, we shall determine the density of the marble. This can be obtained as follow:

Mass of marble = 5 g

Volume of marble = 8 mL

Density of marble =?

Density = mass / volume

Density of marble = 5 / 8

Density of marble = 0.625 g/mL

2. Determination of the work done.

Mass (m) = 1000 Kg

Height (h) = 20 m

Acceleration due to gravity (g) = 10 m/s²

Workdone (Wd) =?

The work done can be obtained as follow:

Wd = mgh

Wd = 1000 × 10 × 20

Wd= 2×10⁵ J

3. Determination of the potential energy.

Mass (m) = 12 Kg

Height (h) = 42 m

Acceleration due to gravity (g) = 10 m/s²

Potential energy (PE) =?

The potential energy can be obtained as follow:

PE = mgh

PE = 12 × 10 × 42

PE = 5040 J

4. Determination of the kinetic energy.

Mass (m) = 1500 Kg

Velocity (v) = 10 m/s

Kinetic energy (KE) =?

The kinetic energy can be obtained as follow:

KE = ½mv²

KE = ½ × 1500 × 10²

KE = 750 × 100

KE = 75000 J

6 0
3 years ago
What is the relationship between Potential energy and KInetic energy in a system?
steposvetlana [31]

Answer:

A soma dos dois tipos de energia, potencial e cinética, resultam na energia mecânica. Ou seja, ambas compõe a energia mecânica.

8 0
3 years ago
What does Newton's law all about?<br>​
KengaRu [80]
Newton's law is all about motion
5 0
3 years ago
At a horse race, all horses started from rest. As soon as the gates were open the horses started to trot. After 300s, Blacky was
Bas_tet [7]
Acceleration<span> is a vector quantity that is defined as the rate at which an object changes its velocity. An object is </span>accelerating<span> if it is changing its velocity. It can be calculated by the expression:

a = v2 - v1 / t

From the given in the problem, we can solve for v2, the final velocity:

3 = v2 - 0 / 300
v2 = 900 m/s</span>
4 0
4 years ago
A coil of wire with 50 turns lies in the plane of the page and has an initial area of 0.180 m2. The coil is now stretched to hav
butalik [34]

Answer:

Explanation:

Given that,

Number of turns of coil

N = 50 turns

Initial area of plane

A1 = 0.18 m²

The coil it stretch to a no area in time t = 0.1s

No area implies that the final area is 0, A2 = 0 m²

Constant magnetic field strength

B = 1.51 T

EMF?

EMF is given as

Using far away Lenz law

ε = —N• dΦ/dt

Where Φ = BA

Then,

ε = —N• d(BA)/dt

Since B is constant,

ε = —N•B dA/dt

ε = —N•B (∆A/∆t)

ε = —N•B(A2—A1)/(t2-t1)

ε = —50 × 1.51 (0—0.18)/(0.1—0)

ε =—75.5 × —0.18 / 0.1

ε = 135.9 V

The induced EMF is 135.9V

Fleming’s left hand rule stated that if the index finger points toward magnetic flux, the thumb towards the motion of the conductor, then the middle finger points towards the induced emf.

Since the area lines in the plane, then the induced emf will be out of the page

5 0
4 years ago
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