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inysia [295]
3 years ago
15

Ellen needs to move a heavy box across the floor and then place it on a shelf that is four feet above the floor. Which use of ma

chines would most likely require the least amount of force in order to get the box on the shelf?
A. sliding the box up an inclined plane to the shelf
B. rolling the box up an inclined plane on a cart
C. sliding the box across the floor and then lifting it using a pulley
D. rolling the box across the floor in a cart and then using a pulley
Physics
2 answers:
dusya [7]3 years ago
4 0
<span>D. rolling the box across the floor in a cart and then using a pulley </span>
slava [35]3 years ago
4 0

The answer among the choices is option C. Sliding the box across the floor and lifting it using a pulley.

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you are piloting a small plane and you want to reach an airport 450 km due south in 3.0 h a wind is blowing from the west 50.0 k
alex41 [277]

Answer:

You should choose airspeed 158.11 km/h at 18.4° west of south

Explanation:

The distance to the air port is 450 km due to south

You should to reach the airport in 3 hours

→ Velocity = distance ÷ time

→ Distance = 450 km , time = 3 hours

→ The velocity of your plane = 450 ÷ 3 = 150 km/h due to south

A wind is blowing from west 50 km/h

We need to know what heading and airspeed you should choose to

reach your destination

At first we must find the resultant velocity of your plane and the wind

The south and west are perpendicular, then the resultant velocity is

→ v_{R}=\sqrt{(v_{p})^{2}+(v_{w})^{2}}

→ v_{p}=150 km/h ,  v_{w}=50 km/h

→ v_{R}=\sqrt{(150)^{2}+(50)^{2}}=158.11 km/h

To cancel the velocity of the wind, the pilot should maintain the velocity

of the plane at 158.11 km/h

The direction of the velocity is the angle between the resultant velocity

and the vertical (south)

→ The direction of the velocity is tan^{-1}\frac{50}{150}=18.4°

The direction of the velocity is 18.4° west of south

<em>You should choose airspeed 158.11 km/h at 18.4° west of south</em>

8 0
3 years ago
Define the word logrolling in your own words?
Elan Coil [88]
A crazy sport thats kinda dangerous
3 0
2 years ago
Read 2 more answers
if a torque of 55.0 N/m is required and the largest force that can be exerted by you is 135 N what is th e length of the lever a
Whitepunk [10]

Answer:

r=0.41m

Explanation:

Torque is defined as the cross product between the position vector ( the lever arm vector connecting the origin to the point of force application) and the force vector.

\tau=r\times F

Due to the definition of cross product, the magnitude of the torque is given by:

\tau=rFsin\theta

Where \theta is the angle between the force and lever arm vectors. So, the length of the lever arm (r) is minimun when sin\theta is equal to one, solving for r:

r=\frac{\tau}{F}\\r=\frac{55\frac{N}{m}}{135N}\\r=0.41m

7 0
2 years ago
What is the relationship between inertia and mass?
ivann1987 [24]

Answer:

D

Explanation:

The greater the mass, the greater the inertia, and vice versa.

Remark: This means that a more massive object has a greater tendency to resist a change in its state of rest or motion.

8 0
3 years ago
Dams are made wider at the bottom than at the top?
malfutka [58]
Yes dams are made wider at the bottom because the pressure of the water pressure is greater there
8 0
3 years ago
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