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wlad13 [49]
3 years ago
9

You throw a ball straight up. Compare the sign of the work done by gravity while the ball goes up with the sign of the work done

by gravity while it goes down.
a. Work is + on the way up and + on the way down
b. Work is + on the way up and - on the way down
c. Work is - on the way up and + on the way down
d. Work is - on the way up and - on the way down
Physics
1 answer:
Elden [556K]3 years ago
8 0

Answer:

c. Work is - on the way up and + on the way down

Explanation:

Work done is given as the product of the applied force and the displacement of the object.

Work done = F x d

Work done = mg x d

where;

g is acceleration due to gravity = 9.8 m/s²

When the ball goes up, it moves against the force of gravity which tends to pull every object downwards. Since the ball moves against gravity, the work done is negative.

Also, when the ball goes down, it moves in the direction of gravity which acts downwards. Since the ball moves in the same direction as gravity, the work done is positive.

The correct option is "C. Work is negative (-) on the way up and positive (+) on the way down"

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Which natural hazards are most likely to affect Florida, due to its geography? Check all that apply. PLS HELP! I WILL GIVE BEST
zhenek [66]

Answer:

drought, floods, rip currents, tropical cyclones, wildfires

Explanation:

right on edge

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3 years ago
The electric current in a wire is 1.5A. How many electrons flow past a given point in a time of 2s?
kipiarov [429]

Answer:

The amount of electrons that flow in the given time is 3.0 C.

Explanation:

An electric current is defined as the ratio of the quantity of charge flowing through a conductor to the time taken.

i.e           I = \frac{Q}{t} ...................(1)

It is measure in Amperes and can be measured in the laboratory by the use of an ammeter.

In the given question, I = 1.5A, t = 2s, find Q.

From equation 1,

            Q = I × t

                = 1.5 × 2

               = 3.0 Coulombs

The amount of electrons that flow in the given time is 3.0 C.

5 0
3 years ago
While entering a freeway, a car accelerates from rest at a rate of 2.40 m/s2 for 12.0 s. (a) Draw a sketch of the situation. (b)
ArbitrLikvidat [17]

Answer:

a) See attached picture, b) We know the initial velocity = 0, initial position=0, time=12.0s, acceleration=2.40m/s^{2}, c) the car travels 172.8m in those 12 seconds, d) The car's final velocity is 28.8m/s

Explanation:

a) In order to draw a sketch of the situation, I must include the data I know, the data I would like to know and a drawing of the car including the direction of the movement and its acceleration, just like in the attached picture.

b) From the information given by the problem I know:

initial velocity =0

acceleration = 2.40m/s^{2}

time = 12.0 s

initial position = 0

c)

unknown:

displacement.

in order to choose the appropriate equation, I must take the knowns and the unknown and look for a formula I can use to solve for the unknown. I know the initial velocity, initial position, time, acceleration and I want to find out the displacement. The formula that contains all this data is the following:

x=x_{0}+V_{x0}t+\frac{1}{2}a_{x}t^{2}

Once I got the equation I need to find the displacement, I can plug the known values in, like this:

x=0+0(12s)+\frac{1}{2}(2.40\frac{m}{s^{2}} )(12s)^{2}

after cancelling the pertinent units, I get that  my answer will be given in meters. So I get:

x=\frac{1}{2} (2.40\frac{m}{s^{2}} )(12s)^{2}

which solves to:

x=172.8m

So the displacement of the car in 12 seconds is 172.8m, which makes sense taking into account that it will be accelerating for 12 seconds and each second its velocity will increase by 2.4m/s.

d) So, like the previous part of the problem, I know the initial position of the car, the time it travels, the initial velocity and its acceleration. Now I also know what its final position is, so we have more than enough information to find this answer out.

I need to find the final velocity, so I need to use an equation that will use some or all of the known data and the unknown. In order to solve this problem, I can use the following equation:

a=\frac{V_{f}-V_{0} }{t}

Next, since I need to find the final velocity, I can solve the equation just for that, I can start by multiplying both sides by t so I get:

at=V_{f}-V_{0}

and finally I can add V_{0} to both sides so I get:

V_{f}=at+V_{0}

and now I can proceed and substitute the known values:

V_{f}=at+V_{0}

V_{f}=(2.40\frac{m}{s^{2}}} (12s)+0

which solves to:

V_{f}=28.8m/s

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Answer:

16. 68.18 Km/h

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Explanation:

16. Determination of the speed

Distance travelled = 150 Km

Time = 2.2 hours

Speed =?

Speed is simply defined as the distance travelled with time. Mathematically, it is expressed as:

Speed = Distance / time

With the above formula, we can obtain the speed as follow:

Distance travelled = 150 Km

Time = 2.2 hours

Speed =?

Speed = Distance /time

Speed = 150 / 2.2

Speed = 68.18 Km/h

17. Determination of the distance.

Speed = 3 mph

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Karolina [17]

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