A 0.4kg ball has a velocity of 18m/s Calculate the kinetic energy of the ball

How much work would be required to stop the ball

A 7kg bowling ball is brought to a height of 1.5m
What is the increase of potential energy

How much work was required to lift the box to this position?
If the ball is dropped, calculate the velocity of the ball just before it hits the ground

The staples inside a stapler are kept in place by a spring with a relaxed length of 0.115m. If the spring constant is 51.0N/m, how much elastic potential energy( E. P.E) is stored in the spring when its length is 0.150m?

A roller coaster car with a mass of 1200kg starts at rest from a point (A) 20m above the ground.
a) What is the Potential energy of the car at point A?

b) If friction can be ignored, what will be the kinetic energy of the roller coaster at the bottom of the hill?

c) How fast is the roller coaster moving as soon as it reaches the bottom of the hill?

d) How much work must be done to stop the roller coaster as soon as it reaches the bottom of the hill? ( Explain)

Aroll in a paper machine is powered by a separately excited dc machine. operating point 1 (under load): the roll typically operates at 764 rpm and must provide 301 nm of torque to oppose the load of the paper. the armature voltage is 230v for this operating point operating point 2 (no load): when the load is removed the speed of the roll increases to 900 rpm (the field characteristics are unchanged) la ea dev m (a) calculate the maximum torque (units of nm) that the motor can supply with this applied voltage (b) calculate the value of the armature resistance, ra (in ohms) (c) at operating point 1 (loaded condition), the field current, i, and the total input power (armature field), are measured to be to be 10 a and 28,600 w respectively. use this information to calculate the value of the field resistance, rf (in ohms). (d) (d) at operating point 1 (loaded condition), calculate the motor efficiency. express your answer as a percent to at least 2 significant digits. (d) if the field voltage is reduced by 1/2, calculate the new stall torque (in nm) of the motor (f). if the field voltage is reduced by 1/2, calculate the new no-load speed (in rad/sec)

When an object is heated it contracts. a. true b. false

Determine the maximum r-value of the polar equation r =3+3 cos 0