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Anna [14]
3 years ago
12

A crate resting on a rough horizontal floor is to be moved horizontally. The coefficient of static friction is 0.36. To start th

e crate moving with the weakest possible applied force, in what direction should the force be applied ?
Physics
1 answer:
luda_lava [24]3 years ago
5 0

Answer:

Explanation:

The direction of force will be in upward direction making an angle of θ with the vertical .

Reaction force R = mg - F cosθ

Friction force = μR

= .36 (mg - F cosθ )

Horizontal component of applied force

= F sinθ

For equilibrium

F sinθ = .36 (mg - F cosθ)

F sinθ + .36 F cosθ =.36 mg

F (sinθ + .36 cosθ) = .36 mg

F R( cosδsinθ +sinδ cosθ) = .36 mg ( Rcosδ = 1 . Rsinδ= .36 )

F R sin( θ+δ )  = . 36 mg

F = .36 mg / Rsin( θ+δ )

For minimum F , sin( θ+δ ) should be maximum

sin( θ+ δ ) = sin 90

θ+ δ  = 90

Rsinδ / Rcosδ  = .36

δ = 20⁰

θ = 70⁰ Ans

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A deuterium atom is a hydrogen atom with a neutron added to its nucleus. Approximate the binding energy of this nucleus, given t
Mademuasel [1]

Answer:

c. 2 MeV.

Explanation:

The computation of the binding energy is shown below

= [Zm_p + (A - Z)m_n - N]c^2\\\\=[(1) (1.007825u) + (2 - 1 ) ( 1.008665 u) - 2.014102 u]c^2\\\\= (0.002388u)c^2\\\\= (.002388) (931.5 MeV)\\\\=2.22 MeV

= 2 MeV

As 1 MeV = (1 u) c^2

hence, the binding energy is 2 MeV

Therefore the correct option is c.

We simply applied the above formula so that the correct binding energy could come

And, the same is to be considered

8 0
3 years ago
12. A frain moves from rest to a speed of 25 m/s in 30.0 seconds. What is its acceleration?
ziro4ka [17]
  • initial velocity=u=0m/s
  • Final velocity=v=25m/s
  • Time=t=30s

\\ \tt\longmapsto Acceleration=\dfrac{v-u}{t}

\\ \tt\longmapsto Acceleration=\dfrac{25-0}{30}

\\ \tt\longmapsto Acceleration=\dfrac{25}{30}

\\ \tt\longmapsto Acceleration=0.8m/s^2

6 0
3 years ago
A race car has a centripetal acceleration of 13.33 m/s^2 as it goes around a curve. if the curve is a circle with a radius 30 m
anzhelika [568]

Answer:

The speed of the car, v = 19.997 m/s

Explanation:

Given,

The centripetal acceleration of the car, a = 13.33 m/s²

The radius of the curve, r = 30 m

The centripetal force acting on the car is given by the formula

                                   F = mv²/r

Where    v²/r is the acceleration component of the force

                                       a = v²/r

Substituting the values in the above equation

                                        13.33 = v²/30

                                         v² = 13.33 x 30

                                         v² = 399.9

                                         v = 19.997 m/s

Hence, the speed of the car, v = 19.997 m/s

3 0
3 years ago
If a 80kg diver jumps off of a 5 m high dive into a regulation diving pool, how much should the temperature of the pool go up?
Agata [3.3K]

Answer:

The answer cannot be determined.

Explanation:

The energy of the diver when he hits the pool will be equal to its potential energy mgh, and for the temperature of the pool to rise up, this energy has to be converted into the heat energy of the pool.

The change in temperature {\Delta}T then will be

{\Delta}T=\frac{{\Delta}Q}{mc} .

Where m is the mass of water in the pool, c is the specific heat capacity of water, and {\Delta}Q is the added heat which in this case is the energy of the diver.

Since we do not know the mass of the water in the pool, we cannot make this calculation.

7 0
3 years ago
A seesaw is 4.0m long with a pivot at its midpoint. A boy who weighs 400N sits at a distance of 1.5m from the pivot. His sister
bezimeni [28]

Answer:

the girl must sit 2 cm from the pivot at the opposite end of the seesaw.

Explanation:

Given;

length of the seesaw, L = 4.0 m

weight of the boy, W₁ = 400 N

position of the boy from the pivot, d₁ = 1.5 m

weight of her sister, W₂ = 300 N

First, make a sketch of this information given;

                 0---0.5m---------------------Δ--------------------------4m

                         ↓<--------1.5m-------> <---------x--------->↓

                        400 N                                          300N

Apply the principle of moment about the pivot, to determine the value of x;

Sum of anticlockwise moment = sum of clockwise moment

400(1.5) = 300(x)

600 = 300x

x = 600/300

x = 2 cm

Thus, the girl must sit 2 cm from the pivot at the opposite end of the seesaw.

8 0
3 years ago
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