Physics Force & Laws Of Motion Level: High School
Conservation of momentum
Two ice skaters face each other with their hands pressed together . The mass of one of the skaters is 80 kg . When they push apart , the heavier skater moves backward at a velocity of 1.5 m/s , whereas the other skater’s velocity is 2.3 m/s . What is the mass of the other skater in kilograms ?
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 Force & Laws Of Motion Level: High School
If a force accelerates 4.5 kg at 40 m/s^2 , that same force would accelerates 18 kg by how much ?
Physics Force & Laws Of Motion Level: High School
For identical materials , static coefficient of friction be greater than kinetic coefficient of friction .True
False
Physics Force & Laws Of Motion Level: High School
If you exert a force F on an object , the force which the object exerts on you willa. Depend on whether or not you are moving .
b. Depend on the relative masses of you and the object.
c. Depend on whether or not the object is moving.
d. Be –F in all cases.
Physics Force & Laws Of Motion Level: High School
A 4-kg mass and a 10-kg mass are acted on by the same constant net force during the same amount of time . Both masses are at rest before the force is applied . The 10 kg mass moves a distance X1 and the 4 kg mass moves a distance X2 as a result . Which of the following statements are true .a. The ratio X1/X2 is equal to 2/5
b. X1 is equal to X2
c. The ratio X1/X2 is equal to 5/2
d. The X1/X2 is equal to (2/5)^2
Physics Force & Laws Of Motion Level: High School
A load of steel of mass 6000 kg rests on the flatbed of a truck , It is held in place by metal brackets that can exert a maximum horizontal force of 8000 N . When the truck is traveling 20 m/s , what is the minimum stopping distance if the load is not to slide forward into the cab ?
Physics Force & Laws Of Motion Level: High School
A team of dogs pulls on a sled that has a mass of 150 kg with a net horizontal force of 300 N , Assuming that there is no friction , what is the acceleration of the sled ?
Physics Force & Laws Of Motion Level: High School
A wooden block slides directly down an inclined plane at a constant velocity of 6 m/s . How large is the coefficient of kinetic friction(A micro k) , if the plane makes an angle of 25 degree with the horizontal ?
Physics Force & Laws Of Motion Level: High School
Conservation of momentum
A two-stage rocket moves in space at a constant velocity of 4850 m/s . The two stages are then separated by a small explosive charge placed between them . Immediately after the explosion the velocity of the 1320 kg upper stage is 5520 m/s in the same direction as before the explosion . What is the velocity (magnitude and direction) of the 2360 kg lower stage after the explosion ?
Physics Force & Laws Of Motion Level: High School
Conservation of momentum
A 57.0 kg person , running horizontally with a velocity of +3.92 m/s , jumps onto a 12.6 kg sled that is initially at rest.(a). Ignoring the effects of friction during the collision, find the velocity of the sled and person as they move away .
(b). The sled and person coast 30.0 m on level snow before coming to rest . What is the coefficient of kinetic friction between the sled and the snow ?
Physics Force & Laws Of Motion Level: High School
A 5.00 kg ball (ball 1) , moving to the right at a velocity of +4.00 m/s on a frictionless table , collides head-on with a stationary 7.90 kg ball (ball 2) . Find the final velocity of the balls if the collision is as specified below .a. Elastic collision.
b. Completely inelastic collision .
Physics Force & Laws Of Motion Level: High School
The lead female character in the movie Diamond Are Forever is standing at the edge of an offshore oil rig . As she fires the gun she is driven back over the edge and into the sea. Suppose the mass of a bullet is 0.007 kg , and its velocity is +700 m/s . Her mass including the gun is 56 kg .(a) What recoil velocity does she acquire in response to a single shot from a stationary position, assuming that no external force keeps her in place ?
(b) Under the same assumption , what would be her recoil velocity if , instead , she shoots a blank cartridge that ejects a mass of 5.0 10-4 kg at a velocity of +700 m/s ?
Physics Force & Laws Of Motion Level: High School
Conservation of momentum
For tests using a ballistocardiograph , a patient lies on a horizontal platform that is supported on jets of air, Because of the air jets, the friction impending the horizontal motion of the platform is negligible . Each time the heart beats , blood is pushed out of the heart in a direction that is nearly parallel to the platform. Since momentum must be conserved , the body and the platform recoil, and this recoil can be detected to provide information about the heart . For each beat, suppose that 0.050 kg of blood is pushed out of the heart with a velocity of +0.25 m/s and that the mass of the patient and the platform is 80 kg . Assuming that the patient does not slip with respect to the platform , and that the patient and the platform start from rest , determine the recoil velocity .
Physics Force & Laws Of Motion Level: High School
When jumping straight down, you can be seriously injured if you land stiff-legged . One way to avoid injury is to bend your knees upon landing to reduce the force of the impact . A 75 kg man just before contact with the ground has a speed of 6.5 m/s .a). In a stiff-legged landing he comes to a halt in 1.7 ms. Find the average net force that acts on him during this time .
b). When he bends his knees , he comes to a halt in 0.13 s. Find the average force now .
c). During the landing , the force on the man points upward , while the force due to gravity points downward . The average net force acting on the man includes both of these forces . Taking into account the direction of these forces , find the force of the ground on the man in parts (a) and (b) .
