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3 years ago

How much heat is needed to boil 120 kg of water ?

1 answer:

7 0

Q = mc∆t, where:
q = energy flow
m = mass, 120 000 g
c = specific heat capacity, 4.81 J/gC
∆t = change in temperature, ~75 (100 - 25, which is room temperature)

Substituting in the values, we get:
q = 120000 x 4.81 x 75 = 43290000 Joules = 43.29 MJ

Hope I helped!! xx

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A 16.0 kg canoe moving to the left at 12.5 m/s makes an elastic head on collision with a 14.0 kg raft moving to the right at 16.

juin [17]

A 16.0 kg canoe moving to the left at 12.5 m/s makes an elastic head on collision with a 14.0 kg raft moving to the right at 16.0 m/s.
After the collision the raft moves to the left at 14.4 m/s assuming water simulates a frictionless surface.
Mass of the canoe (m1) = 16 Kg
Mass of the raft (m2) = 14 Kg
Initial velocity of the canoe (u1) = 12.5 m/s
Initial velocity of the raft (u1) = - 16 m/s [Here, the raft's velocity is negative, because the objects are moving in the opposite direction]
Total momentum of the system = m1u1 + m2u2 = [(16 × 12.5) + (14 × -16)] Kg m/s = (200 - 224) Kg m/s = -24 Kg m/s
Final velocity of the raft (v2) = 14.4 m/s
Let the final velocity of the canoe be v1.
Total momentum of the system after the impact = m1v1 + m2v2 = [(16 × v1) + (14 × 14.4)] Kg m/s = 16v1 Kg + 201.6 Kg m/s
According to the law of conservation of momentum, Total momentum of the system before the impact = Total momentum of the system after the impact
or, -24 Kg m/s = 16v1 Kg + 201.6 Kg m/s
or, -24 Kg m/s - 201.6 Kg m/s = 16v1 Kg
or, -225.6 Kg m/s = 16v1 Kg
or, v1 = -225.6 Kg m/s ÷ 16 Kg
or, v1 = -14.1 m/s

Answer:

The final velocity of the canoe is -14.1 m/s or 14.1 m/s to the right.

Hope you could get an idea from here.

Doubt clarification - use comment section.

6 0

2 years ago

Change a speed of 72.4 miles per hour to its equivalent in meters per second.

4vir4ik [10]

Answer:

Speed in meter/sec will be 32.1777 m /sec

Explanation:

We have given speed = 72.4 miles per hour

We have to convert this speed in meter per second

We know that 1 miles = 1.6 km

So 72.4 miles = 72.4×1.6= 115.84 km

We also know that 1 km = 1000 m

So 115.84 km $=115.84\times 10^3m$

We know that 1 hour = 60×60 = 3600 sec

So $72.4miles/hour=\frac{72.4\times 1600m}{3600sec}=32.1777m/sec$

7 0

4 years ago

Calculate the weight of a 25kg object?

Naily [24]

Mass of 25 kg weight is 25/9.81 slug of mass.

4 0

3 years ago

Why do conductors transfer heat faster than insulators?

Nesterboy [21]

Answer:

Conduction is usually faster in certain solids and liquids than in gases. Materials that are good conductors of thermal energy are called thermal conductors. Metals are especially good thermal conductors because they have freely moving electrons that can transfer thermal energy quickly and easily.

Heat transfer by convection happens through the air, and there are millions of minuscule air spaces between the fibers. Heat transfer by radiation is also slow since one fiber must radiate its heat to another.

When we give heat then kinetic energy is increase and this heat is transferred from hot metal to cold metal through this free electrons. As in insulator the free electrons are negligible so that the heat is not transferred from hot junction to cold junction due to absence of this free electrons.

Explanation:

maek me as brainliest

3 0

2 years ago

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What describes how fast an object is moving and in what direction

Mashcka [7]

Speed is a description of how fast an object moves; velocity is how fast and in what direction it moves. In physics, velocity is speed in a given direction. When we say a car travels at 60 km/h, we are specifying its speed.

6 0

3 years ago

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