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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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Calculate the potential energy of a 5 kg object sitting at the top of a 2 meter ramp.
trapecia [35]
The formula used to find potential energy is <em>P.E. = M * G * H</em> (P.E. is potential energy, M is mass, G is gravitational pull, and H is height). So the answer to your question is <em>5 * 9.8 * 2</em>, which equals 98.
5 0
3 years ago
A 1500 kg car drives around a flat 200-m-diameter circular track at 25m/s. What are the magnitude and direction of the net force
MakcuM [25]

The correct answer to the question is : 9375 N.

CALCULATION:

As per the question, the mass of the car  m = 1500 Kg.

The diametre of the circular track D = 200 m.

Hence, the radius of the circular path R = \frac{D}{2}

                                                                  = \frac{200}{2}\ m

                                                                  = 100 m.

The velocity of the truck v = 25 m/s.

When a body moves in a circular path, the body needs a centripetal force which helps the body stick to the orbit. It acts along the radius and towards the centre.

Hence, the force acting on the car is centripetal force.

The magnitude of the centripetal force is calculated as -

                              Force F = \frac{mv^2}{R}

                                            =  \frac{1500\times (25)^2}{100}\ N

                                            = 9375 N.           [ANS}        

The centripetal force is provided to the car in two ways. It is the friction which provides the necessary centripetal force. Sometimes friction is not sufficient. At that time, the road is banked to some extent which provides the necessary centripetal force.


6 0
3 years ago
Which of the following types of pollution is NOT linked to coal-burning power plant emissions?
Vika [28.1K]
A is not linked. Coal burning is not an effect of acid rain.
~Deceptiøn
8 0
3 years ago
A block of ice at 0 degrees C, whose mass is initially 62 kg, slides along a horizontal surface, starting at a speed of 5.48 m/s
Kryger [21]

The mass of ice melted as a result of friction between the ice and the horizontal surface is 2.78g

<u>Explanation:</u>

Given,

Temperature, T = 0°C

Initial mass, Mi = 62kg

Speed, s = 5.48m/s

Distance, x = 26.8m

Friction is present.

Mass of ice melted = ?

We know,

The amount of energy required for the melting of ice is exactly equal to the initial kinetic energy of the block of ice

and

            Kinetic Energy, KE = \frac{1}{2} mv^2

Therefore,    KE = \frac{62 X  5.48 X 5.48}{2}

KE = 930.94 Joules

Ice melting lateral heat is  334 kJ/kg = 334000 J/kg.

Therefore, the melted mass of the ice = 930.94 / 334000 = 0.00278 kg = 2.78 g.

Thus, The mass of ice melted as a result of friction between the ice and the horizontal surface is 2.78g

4 0
3 years ago
The graph shows projected changes in the populations of the world.
malfutka [58]

Answer: C. Africa

Explanation:

The data given on the graph shows that:

Asia will grow from around 1,300 million to 5,000 million in 2050 which is an increase of:

= 5,000 /1,300 = 3.84 times

Europe will decrease over that period.

Africa will go from around 300 million to 2,000 million which is an increase of:

= 2,000 / 300

= 6.67 times

Mexico

, Central America, Caribbean Islands:

= 900 / 120

= 7.5 times

United States,  Canada, and Greenland:

= 400/120

= 3.33

Oceania:

= 50 / 13

= 3.85

From the options give, Africa will see the greatest increase at 6.67 times its population in 1950.

3 0
3 years ago
Read 2 more answers
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