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2 years ago

The velocity of a bus increases by 20 m/s in 80 seconds. What is the

Physics

1 answer:

EastWind [94]2 years ago

8 0

Answer:

Explanation:

velocity is measured in m/s

acceleration has units m/s^2

so divide the velocity change by the time change:

20 m/s / 80 s = 20 / 80 = .25 m/s^2

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Suppose you ride a bicycle and exert a force of 1000J, but the bicycle's output force is 200J. What is the efficiency of the bic

lorasvet [3.4K]

The efficiency of the bicycle is 20% because 200 out 100 is 2.and ,convert 1000 j out 100 that equal to 10 but,then multiply 2×10 that equal to 20%

8 0

4 years ago

Which of the following objects uses two converging lenses to produce two images, the second of which is virtual, magnified, and

Katyanochek1 [597]

<span>Microscope. A basic microscope is made up of two converging lenses. One reason for using two lenses rather than just one is that it's easier to get higher magnification.</span>

3 0

3 years ago

Heat will flow from a hot object to a cold object until the objects reach

leonid [27]

Answer:

(The first law of thermodynamics) When you put a hot object in contact with a cold one, heat will flow from the warmer to the cooler. As a result, the warmer one will usually cool down and the cooler one will usually warm up. Eventually, they will reach the same temperature and heat flow will stop.

3 0

3 years ago

Read 2 more answers

The three forces shown act on a particle. what is the direction of the resultant of these three forces?

melisa1 [442]

Missing figure: http://d2vlcm61l7u1fs.cloudfront.net/media/f5d/f5d9d0bc-e05f-4cd8-9277-da7cdda3aebf/phpJK1JgJ.png

Solution:
We need to find the magnitude of the resultant on both x- and y-axis.

x-axis) The resultant on the x-axis is
$F_x = 65 N\cdot cos 30^{\circ} - 30 N - 20 N\cdot sin 20^{\circ} = 19.45 N$
in the positive direction.

y-axis) The resultant on the y-axis is
$F_y = 65 N \cdot sin 30^{\circ} - 20 N \cdot cos 20^{\circ} = 13.70 N$
in the positive direction.

Both Fx and Fy are positive, so the resultant is in the first quadrant. We can find the angle and so the direction using
$\tan \alpha = \frac{F_y}{F_x} = \frac{13.70 N}{19.45 N}=0.7$
from which we find
$\alpha=35^{\circ}$

7 0

4 years ago

antiseptic1488 [7]

Answer:

The copper wire stretches 6.25 cm and the steel wire stretches 3.75 cm.

Explanation:

Young's modulus is defined as:

E = stress / strain

E = (F / A) / (dL / L)

E = (F L) / (A dL)

Solving for dL:

dL = (F L) / (A E)

The wires have the same force, length, and cross-sectional area. So:

dL₁ + dL₂ = (FL/A) (1/E₁ + 1/E₂)

Given that dL₁ + dL₂ = 0.10 m, E₁ = 20×10¹⁰ N/m², and E₂ = 12×10¹⁰ N/m²:

0.10 = (FL/A) (1/(20×10¹⁰) + 1/(12×10¹⁰))

FL/A = 0.75×10¹⁰ N/m

Solving for dL₁ and dL₂:

dL₁ = (FL/A) / E₁

dL₁ = (0.75×10¹⁰ N/m) / (20×10¹⁰ N/m²)

dL₁ = 0.0375 m

dL₂ = (FL/A) / E₂

dL₂ = (0.75×10¹⁰ N/m) / (12×10¹⁰ N/m²)

dL₂ = 0.0625 m

The copper wire stretches 6.25 cm and the steel wire stretches 3.75 cm.

5 0

3 years ago