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BigorU [14]
3 years ago
15

A student pushes a box across a rough horizontal floor. If the amount of work done by the student on the box is 100 J and the am

ount of energy dissipated by friction is 40 J, what is the change in kinetic energy of the box
Physics
1 answer:
Archy [21]3 years ago
4 0

Answer:

60J

Explanation:

friction is the opposition to the motion of an object. Before a body can be set in motion, part of the energy or work-done must be used to overcome friction.

While kinetic energy is the energy associated with a body due to its motion.

Since friction tends to oppose the motion of a body,when a body start to move, some of the energy applied to the body to cause its motion is converted to heat due to friction.

Hence if a work-done of 100J is applied to a body that requires 40J of the work to overcome friction, the total change in the kinetic energy can be expressed as

K.E=100J-40J\\K.E=60J\\

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patriot [66]

Answer:

(a) 172.185 N

(b) 53^{\circ}

Solution:

As per the question:

Mass of the child, m = 22.0 kg

Angle, \theta = 37.0^{\circ}

Now,

(a) The magnitude of the normal force exerted by the slide on the child:

F_{N} = mgcos\theta

F_{N} = 22\times 9.8cos37^{\circ} = 172.185\ N

Now,

(b) The angle from the horizontal at which the force is directed is:

90^{\circ} - 37^{\circ} = 53^{\circ}

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3 years ago
A swimming pool measures 5.0 m long x 4.0 m wide x 3.0 mdeep.
QveST [7]

Answer:

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b) 294000 N

Explanation:

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volume is given as (V)= 5m*4m*3m

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b) at either end

P = \frac{F}{A} = P_o + \rho gh

dF = PdA

dF = \rho g w \int h dh

F = \rho g w \frac{h^2}{2}

F = \rho g A \frac{h}{2}           [A = wh]

F = 1000\times 9.8 \times 5\times 4 \times\frac{3}{2}

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a derived quantity is:

C. Speed

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