Answer:
The ball has an initial linear kinetic energy and initial rotational kinetic energy which can both be converted into gravitational potential energy. Therefore the hill with friction will let the ball reach higher.
Explanation:
The ball has an initial linear kinetic energy and initial rotational kinetic energy which can both be converted into gravitational potential energy. Therefore the hill with friction will let the ball reach higher.
This is because:
If we consider the ball initially at rest on a frictionless surface and a force is exerted through the centre of mass of the ball, it will slide across the surface with no rotation, and thus, there will only be translational motion.
Now, if there is friction and force is again applied to the stationary ball, the frictional force will act in the opposite direction to the force but at the edge of the ball that rests on the ground. This friction generates a torque on the ball which starts the rotation.
Therefore, static friction is infact necessary for a ball to begin rolling.
Now, from the top of the ball, it will move at a speed 2v, while the centre of mass of the ball will move at a speed v and lastly, the bottom edge of the ball will instantaneously be at rest. So as the edge touching the ground is stationary, it experiences no friction.
So friction is necessary for a ball to start rolling but once the rolling condition has been met the ball experiences no friction.
Two factors determine whether a substance is a solid, a liquid, or a gas: The kinetic energies of the particles (atoms, molecules, or ions) that make up a substance. Kinetic energy tends to keep the particles moving apart. The attractive intermolecular forces between particles that tend to draw the particles together.
<span>0.52%
First, let's convert that speed into m/s.
150 km/h * 1000 m/km / 3600 s/h = 41.667 m/s
Now let's see how much time gravity has to work on the ball. Divide the distance by the speed.
18 m / 41.667 m/s = 0.431996544 s
Now multiply that time by the gravitational acceleration to see what the vertical component to the ball's speed that gravity adds.
0.431996544 s * 9.8 m/s^2 = 4.233566131 m/s
Use the pythagorean theorem to get the new velocity of the ball.
sqrt(41.667^2 + 4.234^2) = 41.882 m/s
Finally, let's see what the difference is
(41.882 - 41.667)/41.667 = 0.005159959 = 0.5159959%
Rounding to 2 figures, gives 0.52%</span>
Answer:
Animals take in oxygen and give off carbon dioxide.
Explanation:
This is because plants take in our carbon dioxide and give off the oxygen that we as people and animals need to breathe.
Answer: The average speed is 27,24 mph (exactly 1008/37 mph)
Explanation:
This is solved using a three rule: We know the speeds and the distances, what we can obtain from it is the time used. It is done like this:
1h--->18mi
X ---->20 mi, then X=20mi*1h/18mi= 10/9 h=1,111 h
1h--->56mi
X ---->20 mi, then X=20mi*1h/56mi= 5/14 h=0,35714 h
Then the average speed is calculated by taking into account that it was traveled 40mi and the time used was 185/126 h=1,468 h and since speed is distance over time we get the answer. Average speed= 40mi/(185/126 h)=1008/37 mph=27,24 mph.
