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ruslelena [56]
3 years ago
11

A book of mass 3 kg rests on a plank. You tilt one end of the plank and slowly increase the angle of the tilt. The coefficient o

f static friction between the book and the plank is 0.46. What is the maximum angle of tilt for which the book will remain stationary and not slide down the plank?
Physics
1 answer:
bonufazy [111]3 years ago
8 0

Answer: 24.7 degrees Max

Explanation:

m*g = 3 * 9.8 = 29.4 N. = Wt. of book.



Fp = 29.4*sin A = Force parallel to the
plank.



Fn = 29.4*Cos A = Force perpendicular to
the plank.



Fs = u*Fn = 0.46*29.4*Cos A

Fp-Fs = m*a


29.4*sin A - 0.46*29.4*Cos A = m*0 = 0


29.4*Sin A = 0.46*29.4*Cos A


Sin A = 0.46*Cos A


Divide both sides by Cos A:


Sin A/Cos A = 0.46


Replace Sin A/Cos A with Tan A:


Tan A = 0.46


A = 24.7 degrees Max.

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X rays of wavelength 0.0100 nm are directed in the positive direction of an x axis onto a target containing loosely bound electr
Fofino [41]

Answer:

a)  =4.84*10^{-12}

b)= -2.76*10^{-14} J

c)i.e -2.76*10^{-14} J

d)= 0 and the direction of motion is equal to zero

Explanation:

a) compton shift

\Delta\lambda = \frac{h}{mc} (1-cos\theta)

\Delta\lambda = \frac{6.626*10^{-34}}{9.11*10^{-11}3*10^8} (1-cos180)

                        =4.84*10^{-12}

b) the new wavelength

\lambda' = 10.0*10^{-12} +4.84^10^{-12}

               =14.84*10^{-12} m

\Delta E = E' - E

              =hc[\frac{1}{\lambda'}-\frac{1}{\lambda}]

\Delta E = 6.626*10^{-34}*(3*10^8)[\frac{1}{14.84*10^{-12}}-\frac{1}{4.8*10^{-12}}]

= -2.76*10^{-14} J

C)By conservation of energy, the kinetic energy of recoiling electron is equal to the magnitude of energy between the photon energy

i.e -2.76*10^{-14} J

d) the angle between the positive direction of motion

sin\phy = \frac{\lambda_t sin\theta}{\lambda'}

            =\frac{2.43*10^{-12}sin180}{14.84*10^{-12}}  

             = 0

the direction of motion is equal to zero.

4 0
4 years ago
A river has a steady speed 0.500 m/s. A student swims upstream a distance of1.00 km and swims back to the starting point. a) If
Ivahew [28]

Answer:

a) 33.6 min

b) 13.9 min

c)  Intuitively, it takes longer to complete the trip when there is current because, the swimmer spends much more time swimming at the net low speed (0.7 m/s) than the time he spends swimming at higher net speed (1.7 m/s).


Explanation:


The problem deals with relative velocities.

  • Call Vr the speed of the river, which is equal to 0.500 m/s
  • Call Vs the speed of the student in still water, which is equal to 1.20 m/s
  • You know that when the student swims upstream, Vr and Vs are opposed and the net speed will be Vs - Vr
  • And when the student swims downstream, Vr adds to Vs and the net speed will be Vs + Vr.

Now, you can state the equations for each section:

  • distance = speed × time
  • upstream: distance = (Vs - Vr) × t₁ = 1,000 m
  • downstream: distance = (Vs + Vr) × t₂ = 1,000 m

Part a). To state the time, you substitute the known values of Vr and Vs and clear for the time in each equation:

  • (Vs - Vr) × t₁ = 1,000 m
  • (1.20 m/s - 0.500 m/s) t₁ = 1,000 m⇒ t₁ = 1,000 m / 0.70 m/s ≈ 1429 s
  • (1.20 m/s + 0.500 m/s) t₂ = 1,000 m ⇒ t₂ = 1,000 m / 1.7 m/s ≈ 588 s
  • total time = t₁ + t₂ = 1429s + 588s =  2,017s
  • Convert to minutes: 2,0147 s ₓ 1 min / 60s ≈ 33.6 min

Part b) In this part you assume that the complete trip is made at the velocity Vs = 1.20 m/s


  • time = distance / speed = 1,000 m / 1.20 m/s ≈ 833 s ≈ 13.9 min

Part c) Intuitively, it takes longer to complete the trip when there is current because the swimmer spends more time swimming at the net speed of 0.7 m/s than the time than he spends swimming at the net speed of 1.7 m/s.

6 0
4 years ago
Can you please answer theese two qeastion
wel

The first one is C!

I hope the answer helped! please mark brainliest and vote 5 stars! >:)

6 0
3 years ago
Light travels 3,00,000km/s. ls it right velocity or speed?​
MrRa [10]

Answer:

speed

Explanation:

because speed is fast

6 0
4 years ago
Read 2 more answers
A person investing p at a certain rate of simpl interest after 1 2 and3 years it amounted to 1.5 p 2.5 p respectively what will
Ulleksa [173]

Answer: It will amount to 11p after 20 years.

Explanation:

Formula :

Simple interest = Principal x rate x Time              (i)

Amount = Principal + Interest

Amount = Principal +   Principal x rate x Time

Amount =  Principal (1+  rate x Time)                       (ii)

Given: Principal = p

After 1 year , amount = 1.5p

After 3 years , amount = 2.5p

From (ii)

1.5p = p (1+r)\\\\\Rightarrow\ 1.5=1+r\\\\\Rightarrow\ 0.5= r\\\\\Rightarrow r= 0.5

Amount after 20 years = p(1+ 0.5 x 20) = p(1+10)=11p

It will amount to 11p after 20 years.

7 0
3 years ago
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