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natima [27]
3 years ago
9

A weightlifter expends 294 w of power lifting a weight to a height of 2 m in 10 seconds. what mass has he lifted?

Physics
1 answer:
Masja [62]3 years ago
3 0
The power of the weightlifter is equal to the ratio between the work done by it and the time taken:
P= \frac{W}{t}
since we know the power and the time, we can find the work done:
W=Pt=(294 W)(10 s)=2940 J

For the work-energy theorem, this work done by the lifter is equal to the gravitational potential energy gained by the mass, which is given by:
U=mg \Delta h
where m is the mass and \Delta h is the increase in height. Rearranging the formula and using W=U, we can find the mass:
m= \frac{U}{g\Delta h}= \frac{2940 J}{(9.81 m/s^2)(2 m)}=149.8 kg
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3 years ago
Two bodies of mass m₁ & m₂ are moving with the same velocity 'v' K.E. will be greater for??
boyakko [2]

Answer:

the one with a higher mass

Explanation:

The body with more mass will have the greater kinetic energy of the two.

Kinetic energy is the energy due to the motion of body. It is mathematically expressed as:

           K.E  = \frac{1}{2}  m v²

m is the mass

v is the velocity

 Since the velocity of the two bodies are the same, and mass is directly proportional to kinetic energy, the body with more mass will have a higher kinetic energy.

 So between mass m1 and mass m2, the one with a greater mass will have a higher kinetic energy

8 0
2 years ago
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Oduvanchick [21]

Answer:

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Explanation:

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6 0
2 years ago
Read 2 more answers
The next four questions refer to the situation below.
Anna11 [10]

Answer:

 t_{out} = \frac{v_s - v_r}{v_s+v_r} t_{in},      t_{out} = \frac{D}{v_s +v_r}

Explanation:

This in a relative velocity exercise in one dimension,

let's start with the swimmer going downstream

its speed is

         v_{sg 1} = v_{sr} + v_{rg}

The subscripts are s for the swimmer, r for the river and g for the Earth

with the velocity constant we can use the relations of uniform motion

           v_{sg1} = D / t_{out}

           D = v_{sg1}  t_{out}

now let's analyze when the swimmer turns around and returns to the starting point

        v_{sg 2} =  v_{sr}  - v_{rg}

         v_{sg 2} = D / t_{in}

         D = v_{sg 2}  t_{in}

with the distance is the same we can equalize

           v_{sg1} t_{out} = v_{sg2} t_{in}

          t_{out} =  t_{in}

           t_{out} = \frac{v_s - v_r}{v_s+v_r} t_{in}

This must be the answer since the return time is known. If you want to delete this time

            t_{in}= D / v_{sg2}

we substitute

            t_{out} = \frac{v_s - v_r}{v_s+v_r} ()

            t_{out} = \frac{D}{v_s +v_r}

7 0
2 years ago
A 75.0-kg ice skater moving at 10.0 m/s crashes into a stationary skater of equal mass. After the collision, the two skaters mov
Ksenya-84 [330]

Answer:

Explanation:

Momentum change for either skater is mΔv = 75.0(5.0) = 375 kg•m/s

As a change in momentum is equal to an impulse

375 = FΔt

F = 375/0.100 = 3750 N

As 3750 N < 4500 N no bones are broken.

4 0
3 years ago
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