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Vladimir79 [104]
3 years ago
6

Which student is doing work?

Physics
2 answers:
Vilka [71]3 years ago
8 0

Answer:

d

hope this helps

Explanation:

Alja [10]3 years ago
5 0

Answer: C, B

Explanation:

A-Rebecca is just leaning so she isn't doing any work.

B-Marcus is lifting, so that's work.

C-Starr is carrying so that's work too

D-Louis is only studying, he isn't doing nothing that he could make any work

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How much power will it take to move a 50Kg box 10m across a floor that has -50N of Frictional forces in 3 seconds?
likoan [24]

Answer: 83.3 W

Explanation: I think, I’m not sure. If I’m wrong correct me ;)

8 0
3 years ago
vA 61.2-kg circus performer is fired from a cannon that is elevated at an angle of 57.8 ° above the horizontal. The cannon uses
dsp73

Answer:

The effective spring constant of the firing mechanism is 1808N/m.

Explanation:

First, we can use kinematics to obtain the initial velocity of the performer. Since we know the angle at which he was launched, the horizontal distance and the time in which it's traveled, we can calculate the speed by:

v_0_x=\frac{x}{t}\\ \\v_0\cos\theta=\frac{x}{t}\\\\v_0=\frac{x}{t\cos\theta}

(This is correct because the horizontal motion has acceleration zero). Then:

v_0=\frac{20.8m}{(2.60s)\cos57.8\°}\\\\v_0=15.0m/s

Now, we can use energy to obtain the spring constant of the firing mechanism. By the conservation of mechanical energy, considering the instant in which the elastic band is at its maximum stretch as t=0, and the instant in which the performer flies free of the bands as final time, we have:

E_0=E_f\\\\U_e=K\\\\\frac{1}{2}kx^2=\frac{1}{2}mv^2\\\\\implies k=\frac{mv^2}{x^2}

Then, plugging in the given values, we obtain:

k=\frac{(61.2kg)(15.0m/s)^2}{(2.76m)^2}\\\\k=1808N/m

Finally, the effective spring constant of the firing mechanism is 1808N/m.

3 0
3 years ago
A student grabs a piece of paper and tears it from the middle. Which statement best explains the forces involved?
PolarNik [594]

Answer:

b. The normal force between the molecules of the paper is overcome by the contact force of the hands.

Explanation:

The paper molecules are held together by a weak bond. When the student holds the paper on both sides with the center of the paper in between, the student applies two equal forces in the opposite direction of the paper making the paper molecules weaken and separate.

3 0
3 years ago
Read 2 more answers
Giving brainliest!! if you answer correctly :) (30pts)
myrzilka [38]

Answer:

mass = 4kg

Explanation:

Kinetic Energy = 1/2 x m x v²

where m = mass and v = velocity

So,

KE = 50

1/2 × m × 5² = 50

1/2 × m × 25 = 50

m = (50 x 2)/25

m = 100/25

m = 4 kg

8 0
3 years ago
Which is an si metric unit of measurement that is used to record the heat transfer of a solution in a classroom investigation?
kumpel [21]
The SI unit for heat energy is joule
4 0
3 years ago
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