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Tju [1.3M]
3 years ago
15

In order to do work, the force vector must be

Physics
1 answer:
aliina [53]3 years ago
5 0

in the same direction as the displacement vector and the motion

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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

8 0
3 years ago
Read 2 more answers
A.to reduce<br> b.to dispose<br> c.to prevent<br> d.to help
kenny6666 [7]

Answer:

to prevent cuz now for my mind when you prevent it it will not happen to you or nothing happened to you

5 0
3 years ago
Help me answer this ASAP
olga_2 [115]

Answer:

The correct answer is Option A.

7 0
3 years ago
A boy exerts a 36-N horizontal force as he pulls a 52-N sled across a cement sidewalk at a constant speed. What is the coefficie
Vesna [10]

Answer:

0.69

Explanation:

Sum of the forces on the sled in the y direction:

∑F = ma

Fn - 52 N = 0

Fn = 52 N

Sum of the forces on the sled in the x direction:

∑F = ma

36 N - Fn μ = 0

Fn μ = 36 N

μ = 36 N / Fn

Substitute:

μ = 36 N / 52 N

μ = 0.69

7 0
3 years ago
Read 2 more answers
A go-kart and rider have a mass of 14 kg. If the cart accelerates at 6 m/s² during a 40 m sprint in 100 seconds, how much power
Nutka1998 [239]

Answer:

<em>P=33.6 \ W</em>

Explanation:

<u>Mechanical Work and Power</u>

Work is the amount of energy transferred by a force. It's a scalar quantity, with SI units of joules.

Being \vec F the force vector and \vec s the displacement vector, the work is calculated as:

W=\vec F\cdot \vec s

If both the force and displacement are parallel, then we can use the equivalent scalar formula:

W=F.s

Mechanical Power is the amount of energy transferred or converted per unit of time. The SI unit of power is the watt, equal to one joule per second.

The power can be calculated as:

\displaystyle P=\frac {W}{t}

Where W is the work and t is the time.

If an object of mass m has an acceleration a, the net force is:

F=m.a

The go-kart and rider have a mass of m=14 kg and accelerate at 6 m/s^2, thus the net force applied is:

F=14\cdot 6 = 84\ N

The work done by the cart when traveling d= 40 m is:

W=84\cdot 40

W=3,360\ J

Finally, the power for t= 100 seconds is:

\displaystyle P=\frac {3,360}{100}

P=33.6 \ W

5 0
2 years ago
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