Answer:
The kinetic energy INCREASES as the roller coaster goes downhill.
Kinetic energy is greatest at POINT 2
Potential energy is greatest at POINT 1
Kinetic energy is decreasing while potential energy is increasing between points 3 AND 4
Which chart comes closest to the relationship between kinetic energy and potential energy at point 6 - CHART OF ANY POINT IN THE SAME HEIGHT AS OF 6
Explanation:
⇒As the potential energy increases , kinetic energy decreases.
⇒Potential energy here is gravitational potential energy.
⇒Thus, more we move away from the centre of the earth , more will be the gravitational potential energy or decrease in kinetic energy
Answer:
Explanation:
Acceleration is the time rate of change of velocity.
Acceleration and velocity are vectors
If east and north are the positive directions, the east moving vector is reduced to zero and the north moving vector increases from zero to 4 m/s.
There are 3 hours or 10800 seconds between 10 AM and 1 PM
a1 = √((-4)² + 4²) / 10800 = (√32) / 10800 m/s² ≈ 4.2 x 10⁻⁴ m/s²
There are 14400 seconds between 10 AM and 2 PM
The velocity changes are still the same
a2 = √((-4)² + 4²) / 10800 = (√32) / 14400 m/s² ≈ 3.9 x 10⁻⁴ m/s²
Answer:
The tension in the string is quadrupled i.e. increased by a factor of 4.
Explanation:
The tension in the string is the centripetal force. This force is given by
m is the mass, v is the velocity and r is the radius.
It follows that 
, provided m and r are constant.
When v is doubled, the new force, 
, is
Hence, the tension in the string is quadrupled.
Factors affecting friction
The intensity of friction depends on following factors: i) The area involved in friction. ii) The pressure applied on the surfaces. Force = Pressure ´ Area Frictional force will increase, if the area of contact will increase or if pressure applied on the surface increased.
Methods to reduce friction
i) Polish the contact surface. ii) Put oil or grease so that it fills in the small gaps of the flat parts. iii) Use ball bearings to reduce area of contact between rotating parts.
Lubrication
Following methods can be used to reduce friction: Oil is either thin or viscous. It depends upon SAE No. of oil. (SAE means Society of Automotive Engineers). If we use very viscous oil, it does not reach all the parts. Very thin oil will flows away easily and gets wasted. Grease is used in such cases. It is generally used around ball-bearing. Normal grease or oil is never used where there is high pressure, high temperature and high speed. Special lubricants are used in such cases. In cold season the oil becomes thick and in hot season it becomes thin. Therefore selection of lubrication also depends on the season. It is always advisable to refer operating manual of the equipment before selecting the lubricant.
