To solve this problem it is necessary to apply the concepts related to energy conservation. Therefore, the work done will initially be equivalent to the change in kinematic energy. And this kinematic energy will be equivalent to the sum of energy (work) carried out by force and friction. In this way we have to
![E = \frac{1}{2} m (v_f^2-v_i^2)](https://tex.z-dn.net/?f=E%20%3D%20%5Cfrac%7B1%7D%7B2%7D%20m%20%28v_f%5E2-v_i%5E2%29)
![E = \frac{1}{2} (18.8kg)((2.9m/s)^2-(1.5m/s)^2)](https://tex.z-dn.net/?f=E%20%3D%20%5Cfrac%7B1%7D%7B2%7D%20%2818.8kg%29%28%282.9m%2Fs%29%5E2-%281.5m%2Fs%29%5E2%29)
![E = 57.904J](https://tex.z-dn.net/?f=E%20%3D%2057.904J)
Now,
![E = \Delta W](https://tex.z-dn.net/?f=E%20%3D%20%5CDelta%20W)
![E = W_{Force}+W_{Friction}](https://tex.z-dn.net/?f=E%20%3D%20W_%7BForce%7D%2BW_%7BFriction%7D)
For each one we have
![W_{Force} = F dcos(\theta)](https://tex.z-dn.net/?f=W_%7BForce%7D%20%3D%20F%20dcos%28%5Ctheta%29)
![W_{Force} = (160)(6.20*cos(26))](https://tex.z-dn.net/?f=W_%7BForce%7D%20%3D%20%28160%29%286.20%2Acos%2826%29%29)
![W_{Force} = 891.604J](https://tex.z-dn.net/?f=W_%7BForce%7D%20%3D%20891.604J)
Then at the equation of equilibrium of energy we have,
![57.904J = 891.604J+W_{Friction}](https://tex.z-dn.net/?f=57.904J%20%3D%20891.604J%2BW_%7BFriction%7D)
![W_{Friction} = 57.904-891.604](https://tex.z-dn.net/?f=W_%7BFriction%7D%20%3D%2057.904-891.604)
![W_{Friction} = -833.7J](https://tex.z-dn.net/?f=W_%7BFriction%7D%20%3D%20-833.7J)
Therefore the work done by friction on the chair is -833.7J
The sun emits electromagnetic waves with a power of 4 x 1026W. a) Determine the intensity of electromagnetic waves fromthe sun just outside the atmospheres of Venus. b) Determine the intensity ofelectromagnetic waves from the sun just outside the atmospheres ofthe earth.
Answer:
you are right Gravity attracts larger objects only if they are close to one another. If the masses of the objects increase, then the force between them also increases. If distance between the objects increases, then the amount of force also increases. Y Z this is the answer .
Explanation:
Weight of the bus= mass x acceleration due to gravity = 1021x9.8 = 10005.8 N. Hope it helps.