Physics Work,Power & Energy Level: High School
In a perfectly elastic collision :a) Momentum and kinetic energy are conserved
b) Momentum is not conserved but kinetic energy is
c) Neither momentum nor kinetic energy is conserved
d) Momentum is conserved but not kinetic energy
Physics Work,Power & Energy Level: High School
A 50 g of ball of putty moving with a velocity of 3.0 m/s has an inelastic head-on with a stationary mass of 50 g and sticks to it , find the velocity of mass and putty after the collisiona) 1.1 m/s
b) 1.5 m/s
c) 1.7 m/s
d) 1.3 m/s
Physics Work,Power & Energy Level: High School
Conservation of Energy
A simple pendulum with a bob of mass 250 g and length 2.0 m is allowed to fall from a horizontal position . What is the speed of the bob as it passes the lowest point ? (assume g = 9.8 x m/s^2 )a) 6.3 m/s
b) 39 m/s
c) 9.8 m/s
d) 4.9 m/s
Physics Work,Power & Energy Level: High School
The unit of work is ?a) kg m^2/s^2
b) kg m/s
c) kg m^2/s
d) kg m/s^2
Physics Work,Power & Energy Level: High School
If the speed of car is increased by 150 % , (ie, v = 2.5 v) , by what factor will it minimum braking distance be increased , assuming all else is the same ? Ignore the drivers reaction time .
Physics Work,Power & Energy Level: High School
You fire three shots from your gun (lets label the shots A,B,C) One straight up (A) one straight down (B) , and one horizontally (C) . Assume that you shoot from the hip (ie, your hand is in the same place each time, right by your holster ) and you ignore air resistance .(a) Which of the three bullets (A,B or C) will have the greatest speed as it reaches the ground ?
(b) Now include air resistance , how does your answer change and why ?
Physics Work,Power & Energy Level: High School
Conservation of energy
Your car runs out o fuel on a deserted highway . As you car slows to a stop you wonder what happened to all of Kinetic Energy that it just had . Where did this energy go ? Was the total energy conserved ? Explain .
Physics Work,Power & Energy Level: High School
An elevator has a mass of 1200 kg and carries a maximum load of 793 kg . A constant frictional force of 4980 N retards its motion upward . The acceleration of gravity is 9.8 m/s2 . What power must the motor deliver at an instantaneous speed of 4.96 m/s if the elevator is designed to provide upward acceleration of 0.794 m/s2 ? Answer in units of W .
Physics Work,Power & Energy Level: High School
A child pushes horizontally on a box of mass m which moves with constant speed v across a horizontal floor . The coefficient of friction between the box and the floor is mu . At what rate does the child do work on the box ?a) P = mu mg v
b) P = mu mg / v
c) P = mu m vsquared
d) P = v/mu mg
e) P = mgv
Physics Work,Power & Energy Level: High School
Shawn and his bike have a total mass of 43.3 kg . Shawn rides his bike 0.54 km in 17.5 min at a constant velocity . The acceleration of gravity is 9.8 m/s2 . What is the Shawn’s kinetic energy ? Answer in units of J .
Physics Work,Power & Energy Level: High School
You are change of a cannon that exerts a force 13600 N on a cannon ball while the ball is in the barrel of the cannon . The length of the cannon barrel is 2.32 m and the cannon is aimed at a 47.1 degrees angle from the ground . The acceleration of gravity is 9.8 m/s2 . If you want the ball leave the cannon with speed vo = 80.8 m/s . What mass cannon ball must you use ? Answer in units of kg .
Physics Work,Power & Energy Level: High School
A car and driver weighing 7770 N passes a sign stating “Bridge Out 21.6 Ahead.” . She slams on the brakes , and the car decelerates at a constant rate of 13.3 m/s2 . The acceleration of gravity is 9.8 m/s2 . What is the magnitude of the work done stopping the car if the car just stops in time to avoid diving into the water ? Answer in units of J .
Physics Work,Power & Energy Level: High School
A 2.2 kg block is pushed 1.36 m up a vertical wall with constant speed by a constant force of magnitude F applied at an angle of 68.4 degrees with the horizontal . The acceleration of gravity is 9.8 m/s squred . If the coefficient of kinetic friction between the block and the wall is 0.511 , find the work done by F . Answer in units of J .
Physics Work,Power & Energy Level: High School
A baseball is hit high into the upper bleachers of left field . After the ball lands in the bleachers , the work done by gravity and the work done by the air resistance , respectively , will have beena) Wg = negative ; Wa = positive
b) Wg = positive ; Wa = negative
c) Unknown since vital information is lacking .
d) Wg = negative , Wa = negative
e) Wg = positive , Wa = positive
Physics Work,Power & Energy Level: High School
A constant force is exerted for a short distance on a block of mass that is initially at rest on a horizontal frictionless plane . This force gives the block a certain final speed v . Suppose we repeat the experiment but, instead of starting from rest , the block is already moving with constant speed 2v in the direction of force at the moment we begin to apply the force , After we exert the same constant force for the same distance , the increase in the block’s speeda) Cannot be determined from the information provided .
b) is zero.
c) is equal to v
d) is bigger than v
e) is less than v
