All categories

1 year ago

Is work done in this example: A student lifting a heavy backpack off of the floor.

Physics

2 answers:

vagabundo [1.1K]1 year ago

4 0

I don't know what u mean

Maru [420]1 year ago

3 0

You need to add more explaintion of what you are talking about

You might be interested in

A cue ball of mass m1 = 0.325 kg is shot at another billiard ball, with mass m2 = 0.59 kg, which is at rest. The cue ball has an

Roman55 [17]

Answer:

$v_{2f} = \frac{2vm_1}{m_2 + m_1}$

Explanation:

If the collision is elastic and exactly head-on, then we can use the law of momentum conservation for the motion of the 2 balls

Before the collision

$P_i = m_1v$

After the collision

$P_f = m_1v_{1f} + m_2v_{2f}$

So using the law of momentum conservation

$P_i = P_f$

$m_1v = m_1v_{1f} + m_2v_{2f}$

We can solve for the speed of ball 1 post collision in terms of others:

$v_{1f} = v - v_{2f}\frac{m_2}{m_1}$

Their kinetic energy is also conserved before and after collision

$m_1v^2/2 = m_1v_{1f}^2/2 + m_2v_{2f}^2/2$

$m_1v^2 = m_1v_{1f}^2 + m_2v_{2f}^2$

From here we can plug in $v_{1f} = v - v_{2f}\frac{m_2}{m_1}$

$m_1v^2 = m_1\left(v - v_{2f}\frac{m_2}{m_1}\right)^2 + m_2v_{2f}^2$

$m_1v^2 = m_1\left(v^2 - 2vv_{2f}\frac{m_2}{m_1} + v_{2f}^2\frac{m_2^2}{m_1^2}\right) + m_2v_{2f}^2$

$m_1v^2 = m_1v^2 - 2vv_{2f}m_2 + v_{2f}^2\frac{m_2^2}{m_1} + m_2v_{2f}^2$

$v_{2f}^2(m_2 + \frac{m_2^2}{m_1}) - 2vm_2v_{2f} = 0$

$v_{2f}(1 + \frac{m_2}{m_1}) = 2v$

$v_{2f} = \frac{2v}{1 + \frac{m_2}{m_1}} = \frac{2v}{\frac{m_1 + m_2}{m_1}} = \frac{2vm_1}{m_2 + m_1}$

8 0

2 years ago

Read 2 more answers

What is the speed of a wave that has a frequency of 45hz and wavelength of 0.1 meters?

Degger [83]

The answer of speed is 4.5m/s

3 0

2 years ago

The capacitor is now reconnected to the battery, and the plate separation is restored to d. A dielectric plate is slowly moved i

Paha777 [63]

Answer:

U2 = KAε0V2 / (2d)

Explanation:

The dielectric constant K just replaces the "3″ from Part B.

8 0

2 years ago

2. How can people know that they've learned?

photoshop1234 [79]

Answer: People know that they jap e learned by their mistakes or by someone ya being them something

4 0

2 years ago

Kelvin, Celsius, and Fahrenheit are three types of<br> scales

Contact [7]

Answer:

yes, they are.

Explanation:

8 0

2 years ago

Read 2 more answers