How much work is done in accelerating a 2000 kg car from rest to a speed of 30 m/s?

1 answer:

8 0

The work done is the same as the amount of energy increase. The formula for kinetic energy is 122
1
2
m
v
2
.

The initial KE of the car is 12(1000)×202=200,000
1
2
(
1000
)
×
20
2
=
200
,
000
joules.

The final KE of the car is 12(1000)×302=450,000
1
2
(
1000
)
×
30
2
=
450
,
000
joules.

The difference between these is the amount of work done: 450,000−200,000=250,000
450
,
000
−
200
,
000
=
250
,
000
joules.
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A 1.0-kg block moving to the right at speed 3.0 m/s collides with an identical block also moving to the right at a speed 1.0 m/s

____ [38]

Answer:

Speed of both blocks after collision is 2 m/s

Explanation:

It is given that,

Mass of both blocks, m₁ = m₂ = 1 kg

Velocity of first block, u₁ = 3 m/s

Velocity of other block, u₂ = 1 m/s

Since, both blocks stick after collision. So, it is a case of inelastic collision. The momentum remains conserved while the kinetic energy energy gets reduced after the collision. Let v is the common velocity of both blocks. Using the conservation of momentum as :

$m_1u_1+m_2u_2=(m_1+m_2)v$

$v=\dfrac{m_1u_1+m_2u_2}{(m_1+m_2)}$

$v=\dfrac{1\ kg\times 3\ m/s+1\ kg\times 1\ m/s}{2\ kg}$

v = 2 m/s

Hence, their speed after collision is 2 m/s.

7 0

3 years ago

A solution is a homogeneous mixture of one or more solutes dissolved in a solvent. A specific volume of solvent is only able to

Luba_88 [7]

<h3><u>Answer;</u></h3>

C. Supersaturated

<h3><u>Explanation</u>;</h3>

Solutions are homogeneous mixtures that are created by mixing a solute and a solvent. Solute is the substance present in smaller amounts that dissolves in a solvent such as water which is the substance present in larger amount.
A solution, can be<u> unsaturated, saturated or supersaturated. An unsaturated solution</u> is a solution that contains less solute that can be dissolved, it doesn't contain the maximum amount of solute.
<u>A saturated solution</u> is a solution containing the maximum amount of solute that can be dissolved at a given temperature. Any additional solute will remain undissolved in the container.
<u>A supersaturated solution</u> is a solution created when a solution is carefully cooled because it contains more solute than the solubility allows.