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3 years ago

Why doesn’t a machine that increases force break the law of conservation of energy?

Physics

1 answer:

USPshnik [31]3 years ago

8 0

Answer:

A machine in which work input equals work output. energy can be used to do work, work can be used to transfer energy. The change in the kinetic energy of an object is equal to the net work done on the object.

hope this helps

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A motorcycle starts from rest and has a constant acceleration. In a time interval t, it undergoes a displacement x and attains a

iren [92.7K]

Answer:

√(6ax)

Explanation:

Hi!

The question states that during a time t the motorcyle underwent a displacement x at constant acceleration a starting from rest, mathematically we can express it as:

x=(1/2)at^2

Then the we need to find the time t' for which the displacement is 3x

3x=(1/2)a(t')^2

Solving for t':

t'=√(6x/a)

Now, the velocity of the motorcycle as a function of time is:

v(t)=a*t

Evaluating at t=t'

v(t')=a*√(6x/a)=√(6*x*a)

Which is the final velocity

Have a nice day!

3 0

3 years ago

15. If an 800.-kg sports car slows to 13.0 m/s to check out an accident scene and the

goldfiish [28.3K]

The final combined velocity after the collision is 20.2 m/s

Explanation:

We can solve this problem by using the law of conservation of momentum: in fact, in absence of external forces, the total momentum of the two car and of the truck must be conserved before and after the collision.

This means that we can write the following equation:

$p_i = p_f\\m_1 u_1 + m_2 u_2 = (m_1+m_2)v$

where:

$m_1 = 800 kg$ is the mass of the sport car

$u_1 = 13.0 m/s$ is the initial velocity of the car (taking its direction as positive direction)

$m_2 = 1200 kg$ is the mass of the truck

$u_2 = 25.0 m/s$ is the initial velocity of the truck

$v$ is the final combined velocity of the car and the truck, after the collision

Re-arranging the equation and substituting the values, we find the velocity after the collision:

$v=\frac{m_1 u_1 + m_2 u_2}{m_1+m_2}=\frac{(800)(13)+(1200)(25)}{800+1200}=20.2 m/s$

And the positive sign indicates their final direction is the same as the initial direction of the two vehicles.

Learn more about momentum here:

brainly.com/question/7973509

brainly.com/question/6573742

brainly.com/question/2370982

brainly.com/question/9484203

#LearnwithBrainly

5 0

3 years ago

You are pushing a rock along level ground and making the rock speed up. How does the size of the force you exert on the rock com

Aneli [31]

Answer:

The forces are of the same magnitude just opposite directions

Explanation:

Newton's Third law tells us that if body A exerts a force on body B, then B exerts an equal but opposite force on body B. so as you continue to push the rock causing it to accelerate, the rock also continues to push back at you by an equal force in the opposite direction.

4 0

2 years ago

Two radio antennas A and B radiate in phase. Antenna B is a distance of 120 m to the right of antenna A. Consider point Q along

LuckyWell [14K]

Answer:

240 m

120 m

Explanation:

d = Path difference = 120 m

For destructive interference

Path difference

$d=\dfrac{\lambda}{2}\\\Rightarrow \lambda=2d\\\Rightarrow \lambda=2\times 120\\\Rightarrow \lambda=240\ m$

The longest wavelength is 240 m

For constructive interference

$d=\lambda\\\Rightarrow 120\ m=\lambda$

The longest wavelength is 120 m

4 0

3 years ago

What is the best explanation for why a magnet is different from a regular piece of metal?

arlik [135]

Answer:

in a magnet there is a magnetic field that draws ever mental to it

5 0

2 years ago