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3 years ago

I need help on this.

Physics

1 answer:

lana [24]3 years ago

3 0

Answer:

The speed change during the 45-minute trip is 20[mph]

Explanation:

When we see the speed at the 45 minutes this is 20 [mph] and at the 0 minutes the speed is 0 [mph].

Therefore the change is (20 - 0) = 20 [mph]

In the attached image we can see the different figures. In fig 1 we can see the bicycle's speed after 10 minutes when the speed becames constant.

In the fig. 2 we can find the graph when the biker stopped at 30 minutes and took a 15-minute break.

Figures 3 and 4, show the differences when a horizontal line is traced on a position vs time graph, and when the horizontal line is traced in a speed vs time graph.

For fig 3 we can conclude that the body is not moving therefore there is no velocity or acceleration. And for the fig 4, we can realize that the area under the horizontal line represents a displacement during the respective interval of time.

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rjkz [21]

Answer:

The one you have selected is correct. :)

Explanation:

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3 years ago

(TIMED) Anyone know the answer to this question?

KengaRu [80]

I believe C is your answer (also, I am also using tht same exact program!)

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3 years ago

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A coin 15.0 mm in diameter is placed 15.0 cm from a spherical mirror. The coin's image is 5.0 mm in diameter and is erect. Is th

s344n2d4d5 [400]

Answer:

15 cm

Explanation:

$h_{o}$ = Diameter of the coin = 15 mm

$h_{i}$ = Diameter of the image of coin = 5 mm

$d_{o}$ = distance of the coin from mirror = 15 cm

$d_{i}$ = distance of the image of coin from mirror = ?

Using the equation

$\frac{d_{i}}{d_{o}} = \frac{- h_{i}}{h_{o}}$

$\frac{d_{i}}{15} = \frac{- (5)}{15}$

$d_{i}$ = - 5 cm

$R$ = radius of curvature

Using the mirror equation

$\frac{1}{d_{o}} + \frac{1}{d_{i}} = \frac{2}{R}$

$\frac{1}{15} + \frac{1}{- 5} = \frac{2}{R}$

$R$ = - 15 cm

6 0

3 years ago

During a 980. miles cruise, a ship travelled 590 miles in 7 hours first. Then the ship changed its speed for the rest of the tri

vfiekz [6]

Explanation:

The average speed of a modern cruise ship is roughly 20 knots (23 miles per hour), with maximum speeds reaching about 30 knots (34.5 miles per hour).

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3 years ago

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A 0.0450 kg bullet is accelerated from rest to a speed of 425 m/s in a 2.25 kg rifle (which is inititally at rest). The pain of

Mrac [35]

Answer:

If the rifle is held loosely away from the shoulder, the recoil velocity will be of -8.5 m/s, and the kinetic energy the rifle gains will be 81.28 J.

Explanation:

By momentum conservation, and given the bullit and the recoil are in a straight line, the momentum analysis will be unidimentional. As the initial momentum is equal to zero (the masses are at rest), we have that the final momentum equals zero, so

$0=P_{f}=m_{b} *v_{b}+m_{r}*v_{r}$

now we clear $v_{r}$ and use the given data to get that

$v_{r}=-8.5\frac{m}{s}$

But we have to keep in mind that the bullit accelerate from rest to a speed of 425 m/s, then if the rifle were against the shoulder, the recoil velocity would be a fraction of the result obtained, but, as the gun is a few centimeters away from the shoulder, it is assumed that the bullit get to its final velocity, so the kick of the gun, gets to its final velocity $\bold{v_{r}}$ too.

Finally, using $v_{r}$ we calculate the kinetic energy as

$K=\frac{1}{2}m_{r}v_{r}^{2}=81.28J$

3 0

3 years ago

I need help on this.​

I need help on this.