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Rudik [331]
4 years ago
11

While traveling on a horizontal road at speed vi, a driver sees a large rabbit ahead and slams on the brakes. The wheels lock an

d the car begins to slide against the road. The car collides with the rabbit at a final speed of vf, after T seconds of braking. What is the coefficient of kinetic friction of the tires against the road?
Physics
1 answer:
MA_775_DIABLO [31]4 years ago
4 0

Answer:

μk = (Vf - Vc)/(T×g)

Explanation:

Given

Vi = initial velocity of the car

Vf = final velocity of the car

T = Time of application of brakes

g = acceleration due to gravity (known constant)

Let the mass of the car be Mc

Assuming only kinetic frictional force acts on the car as the driver applies the brakes,

The n from Newtown's second law of motion.

Fk = Mc×a

Fk = μk×Mc×g

a = (Vf - Vc)/T

Equating both preceding equation.

μk×Mc×g = Mc × (Vf - Vc)/T

Mc cancels out.

μk = (Vf - Vc)/(T×g)

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a 2.0 kg hoop rolls without slipping on a horizontal surface so that its center proceeds to the right with a constant linear spe
e-lub [12.9K]

Answer:

72 J

Explanation:

Total kinetic energy will be tge sum of rotational and translational energy.

Rotational kinetic energy is given by 0.5I\omega^{2} where I is moment of inertia which is given by mr^{2} and here m is mass, r is radius. Also, v=\omega r hence making \omega the subject then \omega=\frac {v}{r} where v is the velocity.

Rotational kinetic energy=0.5I\omega^{2}=0.5mr^{2}\times(\frac {v}{r})^{2}= 0.5mv^{2}

This is same as the formula for translational kinetic energy which is given by 0.5mv^{2}

Therefore, total kinetic energy= 0.5mv^{2}+0.5mv^{2}=mv^{2}

Substituting m with 2 kg and v with 6 m/s then total energy will be 2\times 6^{2}=72 J

7 0
3 years ago
4. A tuning fork is held over a resonance tube, and resonance occurs when the surface of the water is 12 cm below the top of the
Mrac [35]

As we know that speed of sounds is given as

v = 332 + 0.6t

here we know that

t = 23 degree C

now from above equation we will have

v = 332 + (0.6)(23)

v = 345.8 m/s

now we also know that distance between two consecutive resonance length is half of the wavelength

L_2 - L_1 = \frac{\lambda}{2}

34 - 12 = \frac{\lambda}{2}

\lambda = 44 cm

now we know that

frequency = \frac{speed}{wavelength}

f = \frac{345.8}{0.44} = 786 Hz

so frequency will be 786 Hz

7 0
3 years ago
An object is placed 10 cm from a convex lens of focal length 20 cm. What is the lateral magnification of the object?.
Airida [17]

Answer:Solution

verified

Verified by Toppr

Given:u=−10cm               f=20cm        (convex lens)

To find: v and image's nature.

Solution: From lens formula

v

1

​

−

u

1

​

=

f

1

​

v

1

​

+

10

1

​

=

20

1

​

Explanation:

7 0
2 years ago
What causes resistance in an electric circuit? How is resistance measured?
Sergeeva-Olga [200]
Resistance can be caused by specific resistance tools, like resistors, or loads (the part of the component that uses the electricity) like a light bulb or a speaker. Resistance is measured in ohms and can be measured by a multimeter.
6 0
3 years ago
"if a 20 and a 40 ohm resistor are wired in parallel to a 20v source, what will be the current in the 40 ohm resistor?"
choli [55]

In parallel, neither resistor knows about the other one, and they have no effect on each other.

Each resistor is connected straight to the battery terminals. If the battery is hefty enough, it supplies current to each resistor as if the other one weren't there.

Current through a resistor = (voltage across it) / (its resistance).

Current = (20 V) / (40 ohms)

Current = 1/2 Ampere.

4 0
3 years ago
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