Your teacher's SUV can go from rest to 25 m/s (roughly 55mph) in 10 seconds, The car's velocity changes at a uniform rate.

A driver in a 2000 kg Porsche wishes to pass to pass a slow-moving school bus on a four-lane road. What is the average power in

Kryger [21]

The average power is $3.0\cdot 10^6 W$

Explanation:

First of all, we calculate the work done to accelerate the car; according to the work-energy theorem, the work done is equal to the change in kinetic energy of the car:

$W=K_f -K_i= \frac{1}{2}mv^2-\frac{1}{2}mu^2$

where :

$K_f = \frac{1}{2}mv^2$ is the final kinetic energy of the car, with

m = 2000 kg is the mass of the car

v = 60 m/s is the final speed of the car

$K_i = \frac{1}{2}mu^2$ is the initial kinetic energy of the car, with

u = 30 m/s is initial speed of the car

Soolving:

$W=\frac{1}{2}(2000)(60)^2 - \frac{1}{2}(2000)(30)^2=2.7\cdot 10^6 J$

Now we can find the power required for the acceleration, which is given by

$P=\frac{W}{t}$

where

t = 9 s is the time elapsed

Solving:

$P=\frac{2.7\cdot 10^6}{9}=3.0\cdot 10^6 W$

Learn more about power:

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8 0

3 years ago

Work-Energy Theorem: A 4.0 kg object is moving with speed 2.0 m/s. A 1.0 kg object is moving with speed 4.0 m/s. Both objects en

allsm [11]

The same braking force does work on these objects to slow them down. The work done is equal to their change in kinetic energy:

FΔx = 0.5mv²

F = force, Δx = distance traveled, m = mass, v = speed

Isolate Δx:

Δx = 0.5mv²/F

Calculate Δx for each object.

Object 1: m = 4.0kg, v = 2.0m/s

Δx = 0.5(4.0)(2.0)²/F = 8/F

Object 2: m = 1.0kg, v = 4.0m/s

Δx = 0.5(1.0)(4.0)²/F = 8/F

The two objects travel the same distance before stopping.

4 0

2 years ago

Determine the vector sum of the displacements Δd1 = 2.4 m [32° S of W]; Δd2 = 1.6 m [S]; and Δd3 = 4.9 m [27° S of E].

sergeinik [125]

Answer:

3.44 metres

Explanation:

To determine the vector sum of the displacements Δd1 = 2.4 m [32° S of W]; Δd2 = 1.6 m [S]; and Δd3 = 4.9 m [27° S of E], resolve the given parameters into x - component and y - component.

Resolving into x - component

- 2.4cos32 + 4.9cos27 = 2.3306

Resolving into y - component

- 2.4sin32 - 4.9sin27 - 1.6 = - 2.553

The vector sum of the displacement will be

Sqrt( 2.3^2 + 2.6^2) =

Sqrt ( 11.81)

3.44 m

Therefore, the vector sum of the displacements is 3.44 metres

6 0

2 years ago

Someone just help me

Zanzabum

C according to my calculations

3 0

2 years ago

True or False? In an RL circuit, the larger the value of R (i.e. the resistance of the circuit), the longer it takes the circuit

Luba_88 [7]

Answer:

1.False

2.4 E

Explanation:

1.We have to find the statement is true or false.

We know that

Time constant, $\tau=\frac{L}{R}$

Time constant is inversely proportional to resistance R .It means when R increases then time constant decreases when R decrease then the time constant decreases.

Statement:The larger the value of R ,the longer it takes the circuit to reach its final steady- state value

It is false.

2.Energy stored in inductor,E= $\frac{1}{2}LI^2$

When I'=2I

Then, $E'=\frac{1}{2}L(2I)^2=\frac{1}{2}LI^2\times 4=4 E$

Hence,the new total energy will become 4 E.

3 0

2 years ago