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TEA [102]
2 years ago
8

A 65.0-kg woman steps off a 10.0-m diving platform and drops straight down into the water. 1) If she reaches a depth of 3.20 m,

what is the average resistance force exerted on her by the water? Ignore any effects due to air resistance. (Express your answer to three significant figures in kN)
Physics
1 answer:
timurjin [86]2 years ago
7 0

Answer:

F=2627.6N

Explanation:

The work done by this resistive force while traveling a distance <em>d</em> underwater would be:

W=F.d=-Fd

where the minus sign appears because the force is upwards and the displacement downwards.

This work is equal to the change of mechanical energy. At the diving plataform and underwater, when she stops moving, the woman has no kinetic energy, so all can be written in terms of her total change of gravitational potential energy:

W=\Delta E=U_f-U_i=mgh_f-mgh_i=mg(h_f-h_i)

Putting all together:

F=-\frac{W}{d}=-\frac{mg(h_f-h_i)}{d}=-\frac{(65kg)(9.8m/s^2)(-3.2m-10m)}{3.2m}=2627.6N

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What is force ? <br>question for spammers hehe..​
love history [14]

Answer:

Force: Strength or energy as an attribute of physical action or movement.

6 0
2 years ago
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An object accelerates 3 m/s2 , when a force of 6 N acts on it. What is the object’s mass
telo118 [61]

Answer:

<h2>2 kg</h2>

Explanation:

The mass of the object can be found by using the formula

m =  \frac{f}{a}  \\

f is the force

a is the acceleration

From the question we have

m =  \frac{6}{3}  \\  = 2

We have the final answer as

<h3>2 kg</h3>

Hope this helps you

3 0
2 years ago
What is the time constant of a series circuit where the capacitor is 0.330μF and the resistor is 10Ω ?
PtichkaEL [24]

Answer:

\tau=3.3*10^{-6}s

Explanation:

Take at look to the picture I attached you, using Kirchhoff's current law we get:

C*\frac{dV}{dt}+\frac{V}{R}=0

This is a separable first order differential equation, let's solve it step by step:

Express the equation this way:

\frac{dV}{V}=-\frac{1}{RC}dt

integrate both sides, the left side will be integrated from an initial voltage v to a final voltage V, and the right side from an initial time 0 to a final time t:

\int\limits^V_v {\frac{dV}{V} } =-\int\limits^t_0 {\frac{1}{RC} } \, dt

Evaluating the integrals:

ln(\frac{V}{v})=e^{\frac{-t}{RC} }

natural logarithm to both sides in order to isolate V:

V(t)=ve^{-\frac{t}{RC} }

Where the term RC is called time constant and is given by:

\tau=R*C=10*(0.330*10^{-6})=3.3*10^{-6}s

3 0
2 years ago
If there is an object in top of another object, why does the upper object exert a downward normal force?​
rusak2 [61]

Answer:

This is because normal force is exerted perpendicularly to the point of contact between the upper and lower objects.  

Explanation:

This is because the upper object is still subject to gravitational pull. Therefore, the amount of force it exerts on the lower object due to gravity will be equal to the normal force that acts in the negative direction of gravitational force. Additionally, normal force is evident because the upper object will not go into the lower object.

4 0
3 years ago
Given a particle that has the velocity v(t) = 3 cos(mt) = 3 cos (0.5t) meters, a. Find the acceleration at 3 seconds. b. Find th
dalvyx [7]

Answer:

Explanation:

a )  V = 3 cos(0.5t)

differentiating with respect to t

dv /dt = -3 x .5 sin0.5t

= -1.5 sin0.5t.

acceleration = - 1.5 sin 0.5t

when t = 3 s

acceleration = - 1.5 sin 1.5

= - 1.496 ms⁻²

v = 3 cos.5t

b )  dx/dt = 3 cos 0.5 t

dx = 3 cos 0.5 t dt

integrating on both sides

x = 3 sin .5t / .5

x = 6 sin0.5t

At t = 2 s

x = 6 sin 1

x = 5.05 m

4 0
3 years ago
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