Physics Work,Power & Energy Level: High School
Lisa runs up 4 flights of stairs in 22 s. she weighs 510 N. If each flight rises 310 cm :a) what is her change in potential ?
b) what average power (watts) was required during the 22 s ?
c) what minimum horsepower motor would be required to do this ?
Physics Work,Power & Energy Level: High School
A plant engineer , Donna purchases an electrical motor with has an output of 1500 hp . if it requires 1.20 MW of electricity , what is the efficiency of the motor ?
Physics Work,Power & Energy Level: High School
A simple pendulum , with a 4.4 kg mass and length 75 cm , is released from rest at an angle of 50 degrees .To what height does the mass swing on the other side ?
what is the speed of the mass at the bottom of the swing ?
Physics Work,Power & Energy Level: High School
A spring is characterized by a spring constant of 60 N/m . How much potential energy does it store , when stretched by 1.0 cm ?
Physics Work,Power & Energy Level: High School
A driver traveling at 22 m/s , slows downs her 1500 kg car to stop for a red light . What work is done by the friction force against the wheels ?
Physics Work,Power & Energy Level: High School
Daisy raises a 10 kg to a height of 2.5 m in 2.0 sa) How much work did she do ?
b) How much power was expended ?
c) If she raises it in 1.0 s rather than 2.0 s , how does the work and the power change ?
Physics Work,Power & Energy Level: High School
Mathew pulls his little sister Sarah in a sled on an icy surface (assume no friction) , with a force of 60.0 N at an angle of 37.0 degrees upward from the horizontal . If he pulls her a distance of 12.0 m the work he does is ?
Physics Work,Power & Energy Level: High School
A skier , of mass 60 kg , pushes off the top of the hill with an initial speed of 4.0 m/s . How fast will she be moving after dropping 10 m in elevation ?
Physics Work,Power & Energy Level: High School
Automobile air bag reduce what during a collision ?a) speed of the automobile
b) the forces exerted up on the passenger
c) the kinetic energy transferred to the passenger
d) the impulse exerted up on the passenger
Physics Work,Power & Energy Level: High School
The water slides ends at a height of 1.50 m above the pool . If the person starts from the rest at a point A and lands in the water at a point B which is the dis L = 2.64 m from the haze of the slide , what is the vertical drop h of the water slide ? (no friction)
Physics Work,Power & Energy Level: High School
Various similar boxes are being pushed for 10 m across a floor by a net horizontal force as shown in "click here" . The masses of the boxes and the net horizontal force for each case are given in indicated figures . Rank the change in kinetic energy for each box from the greatest change in kinetic energy to the least change in kinetic energy . All boxes have an initial velocity of + 10 m/s ( + direction is to the right and - to the left with -4< -2) . Greatest 1--------2---------3----------4----------5----------6-----------7----------8---------- Least or , all changes in kinetic energies are the same.-------------- Explain your reasoning
Physics Work,Power & Energy Level: High School
The picture shown in "click here" consist of eight cars that are moving along horizontal roads at specified speeds. Also given are the masses of the cars. All of the cars are the same size and shape, but they are carrying loads with different masses . All of these cars are going to be stopped by plowing into identical barriers . All of the cars are going to be stopped by the same constant force by the barrier. Rank these situation from greatest to least on the basis of the stopping distance that will be needed to stop the cars with the same force . That is , put the first car that requires the longest stopping distance and put last the car that require the shortest distance to stop the car with the same force. Longest 1--------2---------3----------4----------5----------6-----------7----------8---------- Shortest or , all the cars requires the same distance.-------------- Explain your reasoning
Physics Work,Power & Energy Level: High School
Find the vector A which when added to vector B = 270 m/s @ 50 degrees, results in the vector C = 140 m/s @ 10 degrees.a) By graphical construction. Specify the scale used , and label each vector including it's direction angle. Show the centimeter length of each vector as measured with ruler. Re-convert back to units given above (m/s here)
b) By calculation
Physics Work,Power & Energy Level: High School
a) Two children tug on a rope against each other (tug of war) . If each child exerts a pull of 30.N. what is the tension of the rope ?
b) One end of the rope is now tied toa tree and both children tug on the free end with a force of 30N each . Is the rope tension different in this case ? If so , what is it ?
Calculate the normal force Fn exerted by the surface on the block . The numerical data is : m = 2.5 kg; Fa = 15 N; angle 1 = angle 2 = 30 degrees .
Physics Work,Power & Energy Level: High School
A 300g air track glider has mounted on it a toy gun of mass 80 g , which fires a 14.0 g rubber dart . The velocity of the dart as observed in the lab is 10.0 m/s what is the recoil velocity of the glider and gun if they are at rest when the gun is fired ? PART B A light and a heavy body have equal kinetic energies . Which one has the larger momentum ? Display reasoning .