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GenaCL600 [577]

3 years ago

7

An object is initially moving at an unknown velocity. It accelerates at a rate of 2.0 m/s2 to a new velocity of 45 m/s in 10s. W

hat was the initial velocity?

1 answer:

katrin2010 [14]3 years ago

6 0

Answer:

Initial velocity=25m/s

Explanation:

acceleration(a)=2m/s^2

Final velocity(v)=45m/s

Time(t)=10seconds

Initial velocity(u)=?

V=u+axt

45=u+2x10

45=u+20

u=45-20

u=25m/s

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Which, if any, of the heat engines violate(s) the second law of thermodynamics?

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The second law states that the total entropy can never decrese over time for an isolated system

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it took 3.5 hours for a train to travel the distance between two cities at a velocity of 120 miles per hour. How many miles lie

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Given:

Time: 3.5 hrs

Velocity: 120 miles/hr

Now Distance= Speed × Time

Now Velocity and speed have the same magnitude. Velocity being a vector quantity has a definite direction. Whereas speed is a scalar quantity,it indicates only the magnitude an doesn't define any direction.

Hence Distance = Velocity x time

Distance = 3.5 × 120 = 420 miles

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3 years ago

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A toy car having mass m = 1.10 kg collides inelastically with a toy train of mass M = 3.55 kg. Before the collision, the toy tra

kkurt [141]

Answer:

$V_{ft}= 317 cm/s$

ΔK = 2.45 J

Explanation:

a) Using the law of the conservation of the linear momentum:

$P_i = P_f$

Where:

$P_i=M_cV_{ic} + M_tV_{it}$

$P_f = M_cV_{fc} + M_tV_{ft}$

Now:

$M_cV_{ic} + M_tV_{it} = M_cV_{fc} + M_tV_{ft}$

Where $M_c$ is the mass of the car, $V_{ic}$ is the initial velocity of the car, $M_t$ is the mass of train, $V_{fc}$ is the final velocity of the car and $V_{ft}$ is the final velocity of the train.

Replacing data:

$(1.1 kg)(4.95 m/s) + (3.55 kg)(2.2 m/s) = (1.1 kg)(1.8 m/s) + (3.55 kg)V_{ft}$

Solving for $V_{ft}$ :

$V_{ft}= 3.17 m/s$

Changed to cm/s, we get:

$V_{ft}= 3.17*100 = 317 cm/s$

b) The kinetic energy K is calculated as:

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

where M is the mass and V is the velocity.

So, the initial K is:

$K_i = \frac{1}{2}M_cV_{ic}^2+\frac{1}{2}M_tV_{it}^2$

$K_i = \frac{1}{2}(1.1)(4.95)^2+\frac{1}{2}(3.55)(2.2)^2$

$K_i = 22.06 J$

And the final K is:

$K_f = \frac{1}{2}M_cV_{fc}^2+\frac{1}{2}M_tV_{ft}^2$

$K_f = \frac{1}{2}(1.1)(1.8)^2+\frac{1}{2}(3.55)(3.17)^2$

$K_f = \frac{1}{2}(1.1)(1.8)^2+\frac{1}{2}(3.55)(3.17)^2$

$K_f = 19.61 J$

Finally, the change in the total kinetic energy is:

ΔK = Kf - Ki = 22.06 - 19.61 = 2.45 J

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3 years ago

If the error in the angle is 0.50, the error in sin 90o is

Sindrei [870]

At the given erro in angle, the error in the measurement of sin 90 degrees would be 0.001.

<h3>Percentage error</h3>

The percentage error of any measurement is obtained from the ratio of the error to the actual measurement.

The error of sin 90 degrees is calculated as follows;

sin 90 = 1

error in measurement = sin(90 - 0.5)

error in measurement = sin(89.5) = 0.999

<h3>Error in sin 90 degrees</h3>

Error in sin 90 degrees = 1 - 0.999

Error in sin 90 degrees = 0.001

Thus, at the given erro in angle, the error in sin 90 degrees would be 0.001.

Learn more about error in measurement here: brainly.com/question/26668346

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