What is a question that an engineer might have about a can opener?

If you wished to warm 100 kg of water by 15 degrees celsius for your bath, how much heat would be required? (give your answer in

Anit [1.1K]

For the answer to the question above,
Q = amount of heat (kJ) 
cp = specific heat capacity (kJ/kg.K) = 4.187 kJ/kgK 
m = mass (kg) 
dT = temperature difference between hot and cold side (K). Note: dt in °C = dt in Kelvin 

Q = 100kg * (4.187 kJ/kgK) * 15 K 
Q = 6,280.5 KJ = 6,280,500 J = 1,501,075.5 cal

6 0

3 years ago

Which value is equivalent to 7.2 kilograms? A. 720 grams B. 7,200 grams C. 72,000 grams D. 720 milligrams E. 7,200 milligrams

Aneli [31]

1 kilogram = 1,000 grams
1 kilogram = 1,000,000 milligrams

8 0

3 years ago

Read 2 more answers

Two blocks in contact with each other are pushed to the right across a rough horizontal surface by the two forces shown. If the

ale4655 [162]

I assume the blocks are pushed together at constant speed, and it's not so important but I'll also assume it's the smaller block being pushed up against the larger one. (The opposite arrangement works out much the same way.)

Consider the forces acting on either block. Let the direction in which the blocks are being pushed by the positive direction.

The 2.0-kg block feels

• the downward pull of its own weight, (2.0 kg) g

• the upward normal force of the surface, magnitude n₁

• kinetic friction, mag. f₁ = 0.30n₁, pointing in the negative horizontal direction

• the contact force of the larger block, mag. c₁, also pointing in the negative horizontal direction

• the applied force, mag. F, pointing in the positive horizontal direction

Meanwhile the 3.0-kg block feels

• its own weight, (3.0 kg) g, pointing downward

• normal force, mag. n₂, pointing upward

• kinetic friction, mag. f₂ = 0.30n₂, pointing in the negative horizontal direction

• contact force from the smaller block, mag. c₂, pointing in the positive horizontal direction (this is the force that is causing the larger block to move)

Notice the contact forces form an action-reaction pair, so that c₁ = c₂, so we only need to find one of these, and we can get it right away from the net forces acting on the 3.0-kg block in the vertical and horizontal directions:

• net vertical force:

n₂ - (3.0 kg) g = 0 ==> n₂ = (3.0 kg) g ==> f₂ = 0.30 (3.0 kg) g

• net horizontal force:

c₂ - f₂ = 0 ==> c₂ = 0.30 (3.0 kg) g ≈ 8.8 N

4 0

3 years ago

Two hockey pucks, labeled A and B, are initially at rest on a smooth ice surface and are separated by a distance of 18.0 m . Sim

Nonamiya [84]

Answer:

The distance covered by puck A before collision is $z = 8.56 \ m$