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3 years ago

How would you describe the relationship between the mass of a car and its kinetic energy?

Physics

2 answers:

shtirl [24]3 years ago

8 0

Answer:

A) As the mass of a car increases, its kinetic energy increases.

Explanation:

In the graph, the mass of the car is represented on the x-axis, while the kinetic energy is represented on the y-axis. We see that as the value on the x-axis increases, the value on the y-axis increases as well: so, the kinetic energy increases as the mass increases.

More specifically, there is a direct proportionality between the two variables. In fact, the equation that relates kinetic energy and mass is:

$K=\frac{1}{2}mv^2$

where

m is the mass

v is the speed

K is the kinetic energy

Nataly [62]3 years ago

4 0

As the mass of the car increases, its kinetic energy increases

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The total resistance of resistors in parallel is always _________ the sum of the resistors.

docker41 [41]

A. less than

In fact, the resistance will be less than that of the lowest resistance resistor.

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3 years ago

Read 2 more answers

Part A If the velocity of a pitched ball has a magnitude of 47.5 m/s and the batted ball's velocity is 51.5 m/s in the opposite

nalin [4]

Explanation:

Let us assume that the mass of a pitched ball is 0.145 kg.

Initial velocity of the pitched ball, u = 47.5 m/s

Final speed of the ball, v = -51.5 m/s (in opposite direction)

We need to find the magnitude of the change in momentum of the ball and the impulse applied to it by the bat. The change in momentum of the ball is given by :

$\Delta p=m(v-u)\\\\\Delta p=0.145\times ((-51.5)-47.5)\\\\\Delta p=-14.355\ kg-m/s$

So, the magnitude of the change in momentum of the ball is 14.355 kg-m/s.

Let the the ball remains in contact with the bat for 2.00 ms. The impulse is given by :

$J=\dfrac{\Delta p}{t}\\\\J=\dfrac{14.355}{2\times 10^{-3}}\\\\J=7177.5\ kg-m/s$

Hence, this is the required solution.

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3 years ago

Magnetic field is measured in SI units of a tesla (T), and a current through a wire generates a field around the wire. The large

topjm [15]

Answer:

The answer is 8 N

Explanation:

The Lorentz force for a current carrying wire is

f = I * L x B

So, for magnetic forces to manifest the current must not be parallel to the magnetic field. So the cases where the wire is parallel to the field would result in a force of zero applied on the wires by the magnetic field because the cross product becomes zero.

For the perpendicular cases:

f = I * L * B

f = 80 * 0.1 * 1 = 8 N

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3 years ago

A dentist using a dental drill brings it from rest to maximum operating speed of 391,000 rpm in 2.8 s. Assume that the drill acc

krek1111 [17]

Answer:

$\alpha = 2327.7 \ rev/s^2$

$\theta = 9124.5 \ rev$

Explanation:

From the question we are told that

The maximum angular speed is $w_{max} = 391000 \ rpm = \frac{2 \pi * 391000}{60} = 40950.73 \ rad/s$

The time taken is $t = 2.8 \ s$

The minimum angular speed is $w_{min}= 0 \ rad/s$ this is because it started from rest

Apply the first equation of motion to solve for acceleration we have that

$w_{max} = w_{mini} + \alpha * t$

=> $\alpha = \frac{ w_{max}}{t}$

substituting values

$\alpha = \frac{40950.73}{2.8}$

$\alpha = 14625 .3 \ rad/s^2$

converting to $rev/s^2$

We have

$\alpha = 14625 .3 * 0.159155 \ rev/s^2$

$\alpha = 2327.7 \ rev/s^2$

According to the first equation of motion the angular displacement is mathematically represented as

$\theta = w_{min} * t + \frac{1}{2} * \alpha * t^2$

substituting values

$\theta = 0 * 2.8 + 0.5 * 14625.3 * 2.8^2$

$\theta = 57331.2 \ radian$

converting to revolutions

$revolution = 57331.2 * 0.159155$

$\theta = 9124.5 \ rev$

6 0

3 years ago

A. What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound f

nasty-shy [4]

Answer:

A)828.8Hz

B)869.2Hz

Explanation:

Here is a complete question;

What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound from its siren? Speed of sound is 345m/s

b. What frequency does she receive after the ambulance has passed?

Vs= speed of the ambulance

, We convert to m/s for unit consistency

= 115 km/h= 115km× 1000m/1m × 1hr/3600s= 31.94m/s

Dopler effect is when observed frequency of wave changes with respect to the source or when observed moves relative to transmitting medium can be expressed as

f'=[ (v + vo)/(v- vs)]*f

=[ (v )/(v- vs)]*f

The sign vo and vs depends on vthe direction of the velocity

f= frequency of ambulance siren= 753Hz

v= speed of sound in air= 345m/s

Vo= speed of observer= 0

A) we are to determine the f' of ambulance as heard by person as ambulance approaching.

To find the frequency f' observed by the person we use the expresion below

Then substitute the values

f'=[ (v )/(v- vs)]*f

=[ (345)/(345-31.94)]×753

= 828.8Hz

B)What frequency does she receive after the ambulance has passed?

To find the frequency f' observed by the person we use the expresion below

Then substitute the values

f'=[ (v )/(v + vs)]*f

=[ (345)/(345 + 31.94)]×753

= 869.2Hz

4 0

3 years ago