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3 years ago

While rowing in a race, John uses his arms to exert a force of 155 N per stroke

Physics

1 answer:

Basile [38]3 years ago

6 0

Answer:

Workdone = 2906.25J

Explanation:

Given the following data;

Force, F = 155

Distance, d = 0.75

Stroke, s = 25

Mathematically, work done is given by the formula;

Work done = force * distance * stroke

$W = F * d * s$

Where,

W is the work done

F represents the force acting on a body.

d represents the distance covered by the body.

s is the number of strokes.

Substituting into the equation, we have;

$Workdone = 155*0.75*25$

Workdone = 2906.25J

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A rocket, initially at rest on the ground, accelerates straight upward from rest with constant acceleration 58.8m/s2 . The accel

Zanzabum

Split the operation in two parts. Part A) constant acceleration 58.8m/s^2, Part B) free fall.

Part A)
Height reached, y = a*[t^2] / 2 = 58.8 m/s^2 * [7.00 s]^2 / 2 = 1440.6 m

Now you need the final speed to use it as initial speed of the next part.

Vf = Vo + at = 0 + 58.8m/s^2 * 7.00 s = 411.6 m/s

Part B) Free fall

Maximum height, y max ==> Vf = 0

Vf = Vo - gt ==> t = [Vo - Vf]/g = 411.6 m/s / 9.8 m/s^2 = 42 s

ymax = yo + Vo*t - g[t^2] / 2

ymax = 1440.6 m + 411.6m/s * 42 s - 9.8m/s^2 * [42s]^2 /2
ymax = 1440.6 m + 17287.2m - 8643.6m = 10084.2 m

Answer: ymax = 10084.2m

8 0

3 years ago

A car with a mass of 1.50x10^3 kg starts from rest and accelerates to a speed of 18.0m/s in 12.0 s. assume that the force of res

Luden [163]

The first thing you should know for this case is the definition of distance.
d = v * t
Where,
v = speed
t = time
We have then:
d = v * t
d = 9 * 12 = 108 m
The kinetic energy is:
K = ½mv²
Where,
m: mass
v: speed
K = ½ * 1500 * (18) ² = 2.43 * 10 ^ 5 J
The work due to friction is
w = F * d
Where,
F = Force
d = distance:
w = 400 * 108 = 4.32 * 10 ^ 4
The power will be:
P = (K + work) / t
Where,
t: time
P = 2.86 * 10 ^ 5/12 = 23.9 kW
answer:
the average power developed by the engine is 23.9 kW

8 0

3 years ago

What are the three most abundant gases in the dry atmosphere?

Anastaziya [24]

Answer:

Nitrogen, Oxygen, Argon.

Explanation:

The three (3) most abundant gases in the dry atmosphere are"

- Nitrogen

- Oxygen

- Argon

These are not the only components of dry air. Dry atmosphere is made up of:

- 78.09% Nitrogen;

- 20.95% Oxygen;

- 0.93% Argon;

- 0.04% Carbon dioxide;

- Other gases

6 0

3 years ago

Read 2 more answers

1) A car is traveling down the interstate at 37.1 m/s. The driver sees a cop and quickly slows down. If the driver slows to 29.8

dlinn [17]

Explanation:

1. Acceleration is the change in velocity over time.

a = Δv / Δt

a = (29.8 m/s − 37.1 m/s) / 3 s

a = -2.43 m/s²

2. Work equals force times distance.

W = Fd

W = (87.3 N) (2.04 m)

W = 178 J

3. Power is work per time.

P = W / t

267 W = 1250 J / t

t = 4.68 s

3 0

3 years ago

In example 18. 4 of the text, the deflection angle of the laser beam as it exits the prism is 22. 6º. If the prism had been made

Marrrta [24]

The deflection angle is 37.29º if the prism was made of polystyrene plastic.

What is a laser beam?

Laser beam is a light beam propagating dominantly in one direction.

It is a beam of radiation produced from a laser.

Here given that,

refraction index of glass, n1= 1.52

refraction index of polystyrene plastic, n2 = 1.59

deflection angle, B = 22.6º

For the second surface,

B = 45º - 22.6º

B = 22.40º

Now from the formula of Snell's law:

n1 sinФ = n2 sin B

sin B / sinФ = n1 / n2

sinФ = (sin 22.40º) * ( 1/ 1.59)

Ф = 37.29º

Hence,

The deflection angle is 37.29º if the prism was made of polystyrene plastic.

Learn more about laser beam here:

<u>brainly.com/question/4218151</u>

#SPJ4

3 0

2 years ago