A rock is thrown 0.8 meters into the air. how fast was it thrown?

A boy throws a ball of mass 0.22 kg straight upward with an initial speed of 29 m/s. When the ball returns to the boy, its speed

maksim [4K]

Answer:

The work is -67.76 J

Explanation:

The law of conservation of energy is considered one of one of the fundamental laws of physics and states that the total energy of an isolated system remains constant. except when it is transformed into other types of energy.

This is summed up in the principle that energy can neither be created nor destroyed in the universe, only transformed into other forms of energy.

In this case you must calculate the loss of kinetic energy. This loss is actually the work done against the resistive force in the air. Friction is the only force other than gravity that acts on the ball.

So, the loss of kinetic energy is $\frac{1}{2} *m*(vf^{2} -vi^{2} )$

You know:

mass=m=0.22 kg
Initial velocity of the ball: $vi= 29 \frac{m}{s}$

Final velocity of the ball: $vf= 15 \frac{m}{s}$

Replacing:

$\frac{1}{2} *0.22 kg*(15^{2} -29^{2} )$ = -67.76 J

Friction work is always negative because friction is always against displacement.

The work is -67.76 J

5 0

3 years ago

How are magazine advertisement creating a wrong imperession of young women by doing what?

Nadya [2.5K]

These type of commercials lead to little girls, teenagers, and women in general to feel bad about what they look like themselves and have a negative self image. extra anxiety to fit the role of the ultra thin, perfect woman Can lead to individuals engaging in anorexia, bulimia and over-exertion at the gym in order to attain the “perfectly-sculpted” body:

http://objectificationofads.weebly.com/effects-on-women.html

5 0

2 years ago

A biker first accelerates from 0.0 m/s to 6.0 m/s in 6 s, then continues at this speed for 5 s. What is the total distance trave

Svetradugi [14.3K]

Answer:

48m

Explanation:

Given the following data;

Initial velocity = 0m/s

Final velocity = 6m/s

Time, t = 6 secs

Time, T2 = 5 secs

Mathematically, acceleration is given by the equation;

$Acceleration (a) = \frac{final \; velocity - initial \; velocity}{time}$

Substituting into the equation;

$a = \frac{6 - 0}{6}$

$a = \frac{6}{6}$

Acceleration, a = 1m/s²

To find the distance covered in the first phase;

Solving for distance, we would use the second equation of motion;

$S = ut + \frac {1}{2}at^{2}$

Substituting the values into the equation;

$S = 0(6) + \frac {1}{2}*1*(6)^{2}$

$S = 0 + \frac {1}{2}*1*36$

$S = 0.5 *36$

Distance, S1 = 18m

For the second phase, time T2 = 5 secs;

Mathematically, speed is given by the equation;

$Speed = \frac{distance}{time}$

Making distance the subject of formula, we have;

$Distance, S = speed * time$

Substituting into the above equation;

$Distance, S = 6 * 5$

Distance, S2 = 30m

Total distance = S1 + S2 = 18m + 30m = 48m

Total distance = 48m

Therefore, the total distance traveled by the biker is 48m.

4 0

3 years ago

A tree moves at 30 km/s relative to the Sun. A squirrel jumps from a branch on

tresset_1 [31]

The reasoning is wrong if we look into Newton's Law of gravitation.

Newton's law of gravitation states that every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.

The law is written as follows;

$F = \frac{Gm_1m_2}{r^2}$