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Likurg_2 [28]
3 years ago
12

A 610-N hiker carrying an 11.0-kg backpack hiked up a trail for 23 minutes. At the end of that time, he is 150 m higher than whe

n he started. (a) How much the the backpack weigh? (b) How much work is accomplished to carry the backpack that distance? (c) How much total work is accomplished? (Use the total weight: hiker + backpack.) (d) What is the hiker’s power in watts? (Don’t forget to convert 23 minutes to seconds.)
Physics
1 answer:
lys-0071 [83]3 years ago
7 0

Answer:

a)110 N (assuming g = 10 m/s2 )

b) 16500 J

c) ≅ 11.96 W

Explanation:

a) 150 m is not enough to a sensible change of gravitational acceleration at that level from Earth's surface. Therefore, backback weight is same as when it is in ground level.

W = mg, W = weight of object ; m = mass of the object ; g =  gravitational acceleration felt by object.

By substituting,

W = 11×10 = 110 N (assuming g = 10 m/s2 )

b)  Work done = Energy change

    Work done by lifting the bag = Potential energy change

                                                     = mgh ; h = Vertical height lifted

                                                     = 11×150×10 (assuming g = 10 m/s2 )

                                                     = 16500 J

c) Power = Work done/ time taken

               = 16500/(23×60)                (minutes converted to seconds by multiplying by 60)

               ≅ 11.96 W

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A professional golfer hits a golf ball of mass 46 g with her 5-iron, and the ball first strikes the ground 155 m away. The ball
RideAnS [48]

Answer:

C=2.32\times 10^{-4}\ Ns^2/m^2

Explanation:

It is given that,

Mass of the golf ball, m = 46 g = 0.046 kg

Terminal speed of the ball, v = 44 m/s

The drag force, F_r=Cv^2

Where, C is the drag coefficient. At terminal speed, the weight of the ball is balanced by the drag force.

Cv^2=mg

C=\dfrac{mg}{v^2}

C=\dfrac{0.046\times 9.8}{(44)^2}

C=2.32\times 10^{-4}\ Ns^2/m^2

Hence, this is the required solution.

4 0
3 years ago
A missile is moving 1350 m/s at a 25.0° angle. It needs to hit a target 23,500 m away in a 55.0° direction in 10.20 s. What is d
QveST [7]

Answer:

  The target's velocity is about 1320 m/s in the direction 265.7°.

Explanation:

In order for there to be a collision between missile and target, we must have ...

  (target starting position) + (target movement) = (missile movement)

assuming the missile starts from the origin of all measurements. The missile moves 10.2 seconds before impact, so moves a distance of ...

  (10.2 s)(1350 m/s) = 13,770 m

__

We are interested in the target movement, so we can solve for that:

  (target movement) = (missile movement) - (target starting position)

In terms of meters, this is ...

  (target movement) = 13770∠25° - 23500∠55° ≈ 13467.74∠-94.3°

The target covers this distance in the same 10.2 seconds before collision, so its speed is (13467.74 m)/(10.2 s) ≈ 1320.4 m/s.

As a positive angle, the target's direction is ...

  -94.3° +360° = 265.7°

The direction of the target's velocity is 265.7°.

_____

If you're calculating this by hand, there are a couple of ways you can do it. You can convert to rectangular coordinates and back (perhaps least confusing), or you can use the law of cosines to solve the triangle, then translate angles back to the x-y coordinate plane.

Using rectangular coordinates, we have ...

  13770∠25° = 13770(cos(25°), sin(25°)) ≈ (12479.9, 5819.45)

  23500∠55° = 23500(cos(55°), sin(55°)) ≈ (13479.0, 19250.1)

Then the difference is ...

  (12479.9, 5819.45) -(13479.0, 19250.1) ≈ (-999.188, -13430.6)

and the (3rd-quadrant) angle is ...

  target direction = arctan(-13430.6/-999.188) ≈ -94.3° = 265.7°

__

The target's speed is found by dividing the distance it covers by the time it takes.

  √(13430.6² +999.188²)/10.2 ≈ 1320.36 . . . m/s

3 0
3 years ago
What unit of measure would you use for mass?
creativ13 [48]

grams, pounds, kilos, etc

6 0
3 years ago
Starting at t = 0 s , a horizontal net force F⃗ =( 0.285 N/s )ti^+(-0.460 N/s2 )t2j^ is applied to a box that has an initial mom
Irina-Kira [14]

Answer:

Explanation:

We know that Impulse = force x time

impulse = change in momentum

change in momentum = force x time

Force F = .285 t -.46t²

Since force is variable

change in momentum = ∫ F dt  where F is force

= ∫ .285ti - .46t²j dt

= .285 t² / 2i - .46 t³ / 3 j

When t = 1.9

change in momentum = .285 x 1.9² /2 i  -  .46 x 1.9³ / 3 j

= .514i - 1.05 j

final momentum

= - 3.1 i + 3.9j +.514i - 1.05j

= - 2.586 i + 2.85j

x component = - 2.586

y component = 2.85

7 0
4 years ago
Why does matter increase in volume when it heats up?
ArbitrLikvidat [17]

Answer:All three states of matter (solid, liquid and gas) expand when heated. ... Heat causes the molecules to move faster, (heat energy is converted to kinetic energy ) which means that the volume of a gas increases more than the volume of a solid or liquid.

Explanation:well I tried lol she just copied and pasted faster than I could

8 0
3 years ago
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