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Trava [24]
3 years ago
15

How much time is needed to produce 720 joules of work if 90 watts of power is used

Physics
1 answer:
Sladkaya [172]3 years ago
4 0

Answer:

8 seconds

Explanation:

power (P) is defined as the rate at which work is done.

power is measured in Watts (W) , when the work done is measured in Joules (J) and time in seconds

by the definition of power,

power=\frac{work.done}{time}\\ time=\frac{work.done}{power}\\ =\frac{720J}{90W} \\=8 seconds

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A 5 kg object moving to the right at 4 m/s collides inelastically with a 5 kg object
skad [1K]

Answer:

The linear momentum of a particle with mass m moving with velocity v is defined as

p = mv (7.1)

Linear momentum is a vector . When giving the linear momentum of a particle you must

specify its magnitude and direction. We can see from the definition that its units must be

kg·m

s

. Oddly enough, this combination of SI units does not have a commonly–used named so

we leave it as kg·m

s

!

The momentum of a particle is related to the net force on that particle in a simple way;

since the mass of a particle remains constant, if we take the time derivative of a particle’s

momentum we find

dp

dt = m

dv

dt = ma = Fnet

so that

Fnet =

dp

dt (7.2)

5 0
3 years ago
Which of the following best represents a decomposition reaction?
Fed [463]

Answer: AB-> A+B

Explanation:

Chemical decomposition is the breakdown of a single entity into two or more fragments. Chemical decomposition is usually regarded and defined as the exact opposite of chemical synthesis. In short, the chemical reaction in which two or more products are formed from a single reactant is called a decomposition reaction.

4 0
3 years ago
A diode, which allows current to flow in one direction only, consists of two types of semiconductors joined together.
Nata [24]

Answer:

True.

Explanation:

A diode, which allows current to flow in one direction only, consists of two types of semiconductors joined together.

A semiconductor can be defined as a crystalline solid substance that has its conductivity lying between that of a metal and an insulator, due to the effects of temperature or an addition of an impurity. Semiconductors are classified into two main categories;

1. Extrinsic semiconductor.

2. Intrinsic semiconductor.

An intrinsic semiconductor is a crystalline solid substance that is in its purest form and having no impurities added to it. Examples of intrinsic semiconductor are Germanium and Silicon.

In an intrinsic semiconductor, the number of free electrons is equal to the number of holes. Also, in an intrinsic semiconductor the number of holes and free electrons is directly proportional to the temperature; as the temperature increases, the number of holes and free electrons increases and vice-versa.

In an intrinsic semiconductor, each free electrons (valence electrons) produces a covalent bond.

6 0
3 years ago
A cart of mass m = 0.12 kg moves with a speed v = 0.45 m/s on a frictionless air track and collides with an identical cart that
lina2011 [118]

Answer:

0.006075Joules

Explanation:

The final kinetic energy of the system is expressed as;

KE = 1/2(m1+m2)v²

m1 and m2 are the masses of the two bodies

v is the final velocity of the bodies after collision

get the final velocity using the law of conservation of momentum

m1u1 + m2u2 = (m1+m2)v

0.12(0.45) + 0/12(0) = (0.12+0.12)v

0.054 = 0.24v

v = 0.054/0.24

v = 0.225m/s

Get the final kinetic energy;

KE = 1/2(m1+m2)v

KE = 1/2(0.12+0.12)(0.225)²

KE = 1/2(0.24)(0.050625)

KE = 0.12*0.050625

KE = 0.006075Joules

Hence the final kinetic energy of the system is 0.006075Joules

5 0
2 years ago
Assume that the home construction industry is perfectly competitive and in long-run competitive equilibrium. It follows that: A.
olga nikolaevna [1]

Answer:

B. Marginal cost equals long-run average total cost.

Explanation:

The zero profit condition implies that entry continues until all firms are producing at minimum long run average total cost. Since the marginal cost curve cuts the long run average total cost curve at its minimum point, marginal cost and long run average total cost must be equal in long run equilibrium.

4 0
3 years ago
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