What unit is used for distance? 1.s 2.m 3.m/s2 4.m/s

Which car has the most kinetic energy?

mixas84 [53]

Answer:

B. A car of mass 2000 kg with speed 7 m/s

Explanation:

The kinetic energy of an object is given by:

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

where m is the mass of the object and v is its speed.

From the formula, we see that the larger the mass and the speed of the object, the larger its kinetic energy. Among the choices given, we see that the car with largest mass and largest speed is car B, which has a mass of 2000 kg and speed of 7 m/s. Its kinetic energy is:

$K=\frac{1}{2}(2000 kg)(7 m/s)^2=49,000 J$

We can verify that the other cars have smaller kinetic energy. In fact:

- Car A: $K=\frac{1}{2}(1000 kg)(3 m/s)^2=4,500 J$

- Car C: $K=\frac{1}{2}(1000 kg)(7 m/s)^2=24,500 J$

- Car D: $K=\frac{1}{2}(2000 kg)(3 m/s)^2=9,000 J$

So, car B is the one which has most kinetic energy.

5 0

4 years ago

An airplane is flying over the South Pole. Which arrow correctly shows the direction gravity pulls the plane? (2 points)

tatyana61 [14]

Answer:

Explanation:

2

3 0

3 years ago

Read 2 more answers

In a nuclear power plant, the temperature of the water in the reactor is above 100°C because of what?

SVETLANKA909090 [29]

Answer:

The temperature of the water increases because the nuclear reactor heats it producing steam

Explanation:

The nuclear power plants are usually defined as those thermal plants where the nuclear reactors are used in order to generate heat that eventually leads to the rotating of the turbines and produces electricity. Here the nuclear reactor heats the water, and it increases above a temperature of 100°C, where this heat energy plays a key role in the entire process. It is an efficient method as it does not lead to the emission of any green house gases that are harmful to the environment.

8 0

3 years ago

Pete is driving down 7th Street. He

lukranit [14]

Answer:

v=10.75m/s

Explanation:

It is given that,

Pete drives 215 Meters in 20 seconds. He is driving down 7th floor. We need to find his speed.

Speed = distance/time

⇒

$v=\dfrac{215\ m}{20\ s}\\\\v=10.75\ m/s$

Hence, the speed of Pete is 10.75 m/s.

8 0

4 years ago

1. What is the wave speed of a wave that has a frequency of 100 Hz and a wavelength of 0.30 m?

aivan3 [116]

Answer:

1. v = 30 m/s

2. v = 5 m/s

3. f = 40 Hz

4. f = 400 Hz

5. f = 300 Hz

6. λ = 0.772 m

7. λ = 0.386 m

8. λ = 0.625 m

9. v = 100 m/s

10. v = 50 m/s

Explanation:

The relationship between frequency, wavelength, and speed of a wave is given by the following formula:

$v = f\lambda$

where,

v = speed of wave

f = frequency of wave

λ = wavelength

1.

f = 100 Hz

λ = 0.3 m

Therefore,

v = (100 Hz)(0.3 m)

v = 30 m/s

2.

f = 50 Hz

λ = 0.1 m

v = (50 Hz)(0.1 m)

v = 5 m/s

3.

v = 20 m/s

λ = 0.5 m

$f = \frac{v}{\lambda} = \frac{20\ m/s}{0.5\ m}$

f = 40 Hz

4.

v = 80 m/s

λ = 0.2 m

$f = \frac{v}{\lambda}=\frac{80\ m/s}{0.2\ m}$

f = 400 Hz

5.

v = 120 m/s

λ = 0.4 m

$f = \frac{v}{\lambda}=\frac{120\ m/s}{0.4\ m}$

f = 300 Hz

6.

v = 340 m/s

f = 440 Hz

$\lambda = \frac{v}{f}=\frac{340\ m/s}{440\ Hz}\\$

λ = 0.772 m

7.

v = 340 m/s

f = 880 Hz

$\lambda = \frac{v}{f}=\frac{340\ m/s}{880\ Hz}\\$

λ = 0.386 m

8.

v = 250 m/s

f = 400 Hz

$\lambda = \frac{v}{f}=\frac{250\ m/s}{400\ Hz}\\$

λ = 0.625 m

9.

f = 50 Hz

λ = 2 m

v = (50 Hz)(2 m)

v = 100 m/s

10.

f = 100 Hz

λ = 0.5 m

v = (100 Hz)(0.5 m)

v = 50 m/s

6 0

3 years ago