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2 years ago

The work done by static friction can be : a. Zero

Physics

1 answer:

mario62 [17]2 years ago

5 0

Answer:

A. Zero

Explanation:

The definition of work is related with the energy that a force 'F' implies in a displacement 'Δx'; it means that it is necessary that the body which is over the force comes under a displacement to develop work. The static friction is a force which is only present when there is no movement; when a force overcome the static friction force, the dynamic friction force appears and it is said that the static one disappear. In that sense, the static friction won't ever be a force that can induce a displacement, so the work done by this force will always be zero.

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When a 0.622 kg basketball hits the floor, its velocity changes from 4.23 m/s down to 3.85 m/s up. If the ball was in contact wi

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when the ball hits the floor and bounces back the momentum of the ball changes.

the rate of change of momentum is the force exerted by the floor on it.

the equation for the force exerted is

f = rate of change of momentum

$f = \frac{mv - mu}{t}$

v is the final velocity which is - 3.85 m/s

u is initial velocity - 4.23 m/s

m = 0.622 kg

time is the impact time of the ball in contact with the floor - 0.0266 s

substituting the values

$f = \frac{0.622 kg (3.85 m/s - (-)4.23 m/s)}{0.0266}$

since the ball is going down, we take that as negative and ball going upwards as positive.

f = 189 N

the force exerted from the floor is 189 N

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3 years ago

Look at the circuit below. What is the voltage between points C and D?

stepan [7]

Option c) 1.5 V

Explanation:

<em>As the circuit is build in series first we will find the current passing through the complete circuit. Current stays the same in each element is the series cirucuit, however, the voltage is different.</em>

Voltage is given by the following formula:

V = IR

<em>Because we have to find current through whole circuit, we will first find resistance of the whole circuit.</em>

Equivalent Resistance R(eq): R1 + R2 = 60 + 60 = 120 ohm

Current passing through whole circuit be:

$I = \frac{V}{R(eq)}\\I = \frac{3}{120}$ = 0.025

Now we will find out the voltage between C and D:

Current stays the same in series circuit: I = 0.025 c

Resistance between C and D is, R = 60 ohm

Voltage becomes, V = IR = 0.025 * 60 = 1.5 V

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2 years ago

Read 2 more answers

The resistance (R) of a copper wire varies directly as its length (L). Write this relation as a formula using k as the constant

Drupady [299]

Answer:

Explanation:

According to ohm's law current flowing in a conductor is directly proportional to the voltage applied across two end of conductor.

i.e. $V\propto R$

$V=R I$

where R=resistance

$R\propto L$

$R\propto \frac{1}{d^2}$

whee L and d are length and Diameter

thus $R=k \frac{L}{d^2}$

where k=constant of Variation

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3 years ago

If the absolute pressure of gas is 550.280 kPa, its gauge pressure is

RUDIKE [14]

pressure absolute = pressure gage + pressure atmosphere

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3 years ago

Consult Multiple-Concept Example 5 to review the concepts on which this problem depends. A light bulb emits light uniformly in a

den301095 [7]

Answer:

a. 0.332 W/m² b. 11.2 V/m c. 15.8 V/m

Explanation:

(a) the average intensity of the light,

Intensity, I = P/A where P = average power = 150.0 W and A = area through which the power emits = 4πr² where r = distance from bulb = 6 m.

So, I = P/A = P/4πr²

Substituting the values of the variables into the equation, we have

I = P/4πr²

I = 150.0 W/4π(6 m)²

I = 150.0 W/4π(36 m²)

I = 150.0 W/452.39 m²

I = 0.332 W/m²

(b) the rms value of the electric field,

Since Intensity, I = E²/cμ₀ where E = rms value of electric field, c = speed of light = 3 × 10⁸ m/s and μ₀ = permeability of free space = 4π × 10⁻⁷ H/m.

Making E subject of the formula, we have

E² = Icμ₀

E = √(Icμ₀)

Since I = 0.332 W/m², substituting the other terms into the equation, we have

E = √(0.332 W/m² × 3 × 10⁸ m/s × 4π × 10⁻⁷ H/m.)

E = √(12.5 × 10)

E = √125 V/m

E = 11.18 V/m

E ≅ 11.2 V/m

(c) the peak value of the electric field.

The peak value of electric field, E' is gotten from E = E'/√2 where E = rms value of electric field.

So, E' = √2E

= √2 × 11.2 V/m

= 15.81 V/m

≅ 15.8 V/m

6 0

3 years ago