Physics Work,Power & Energy Level: High School
The loaded cab of an elevator has a mass of 3.0 x 10^3 kg and moves 210 m up the shaft in 23 s at constant speed . At what average rate does the force from the cable do work on the cab ?
Physics Work,Power & Energy Level: High School
A force F = (cx – 3.00 x^2)I acts on a particle as the particle moves along an x axis , with F in newtons , x in meters , and c a constant . At x = 0, the particles kinetic energy is 20.0 J: at x = 3.00 m , it is 11.0 J , Find c .
Physics Work,Power & Energy Level: High School
A 5.0 kg block moves in a straight line on a horizontal frictionless surface under the influence of a force that varies with position . How much work is done by the force as the block moves from the origin to x = 8.0 m, and (f) x = 9.0 m .
Physics Work,Power & Energy Level: High School
A spring and block are in the arrangement . When the block is pulled out to x = +4.0 cm, we must apply a force of magnitude 360 N to hold it there, We pull the block to x = 11 cm and then release it. How much work does the spring do on the block when the block moves from x1 = +5.0 cm to(a) x = +3.0 cm,
(b) x = -3.0 cm
(c) x = -5.0 cm
(d) x = -9.0 cm
Physics Work,Power & Energy Level: High School
My professor likes to write a table for energy conservation (kinetic energy , gravitational potential energy , and total ). Why does the total always become the kinetic energy even though there is also the GPE ?
Physics Work,Power & Energy Level: High School
A friend claims that he can hold on to a 11 kg child in a 64 mi/h collision lasting for 0.05 s as he has his seat belt on . To prove that the violent forces during a collision will tear the child from his arms , calculate the magnitude of the needed retarding force . (A child should always be in a toddler seat secured with a seat belt in the back seat of a car)
Physics Work,Power & Energy Level: High School
An 8.0 kg mass moving east at 15.6 m/s on a frictionless horizontal surface collides with a 10.0 kg object that is initially at rest . After the collision , the 8.00 kg object moves south at 3.90 m/s .a) What is the velocity of the 10.0 kg object after the collision ?
b) What percentage of the initial kinetic energy is lost in the collision ?
Physics Work,Power & Energy Level: High School
A large asteroid is on a collision course with the earth , the mass of the asteroid is 5.0 x 10e9 metric tons and it is approaching at a velocity of 42000 km/hr. Calculate the kinetic energy of the asteroid in joules . The mass of the earth is 6 x 10e24 kg and g , the acceleration due to gravity is 9.8 m/s squared .
Physics Work,Power & Energy Level: High School
A construction crane with mass 22000 kg lifts a large building stone with mass 2000 kg to position 30 meters above the ground in 50 seconds . Calculate the power in watts (W) consumed by the crane during the lift .
Physics Work,Power & Energy Level: High School
Vertical Circle Or loop the loop
A road over a bridge has the form of a vertical circular arc of radius 20 m . What is the fastest speed at which a car can cross the bridge without leaving the ground at the crest of the road ?
Physics Work,Power & Energy Level: High School
A man mass 80 kg rides a bicycle mass 20 kg at steady speed 4.0 ms^-1 up a road which rides 1 m every 20 m along its length . What power is the cyclist delivering if there is constant resistance to motion of 20 N ?
Physics Work,Power & Energy Level: High School
A 10 kg block with initial downward velocity of 9 m/s , slides down a rebounding ramp from an initial height , h1 = 30 m and rebound to a height , h2 = 10 m .a. Neglecting friction , assume the mass continues moving upward , what is its speed at the right hand side of the rebound ramp at height h2 ?
b. Assuming friction , suppose the block stops exactly at the height of the right hand rebound point , h2 , How much energy went into friction ?
Physics Work,Power & Energy Level: High School
Suppose a 0.020 kg bullet traveling at 230 m/s strikes a moist clay mud pile and penetrates it to a distance , s = 10 cm . Finda. The total work required to stop the bullet .
b. The force acting on the bullet .
c. Suppose it takes only 0.01 seconds to stop the bullet from (4a) above . What is the stopping power of clay mud ?
Physics Work,Power & Energy Level: High School
A jet with full payload mass of Mj = 25000 kg, initially at rest, accelerates uniformly to the right at a = 4 m/s . If it requires 40 sec to reach take off speed , find .a. The KE of the jet.
b. At take off the jet fires a missile of mass = 1000 kg with v = 300 m/s in the same direction . Find KE of the missile .
c. Find the liner momentum of the jet at takeoff.
d. Find the momentum , of the missile.
e. Find the jet liner momentum , after firing the missile .
Physics Work,Power & Energy Level: High School
A 10 kg object is pushed horizontally along the floor from rest until a speed of 30 m/s is obtained .a. What is “a” at a distance s = 6m.
b. Compute the work (KE) done on the mass.
c. Compute the force , F , developed as a result of (a) and (b) above.
d. Suppose the object was pushed downward at an angle of 30 degrees with respect to the horizontal . Compute the work done on the mass .
