Physics Work,Power & Energy Level: High School
Collision
An 8.00 kg mass moving east at 14.3 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 3.50 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
Inelastic Collision
A railroad car of mass 2.80 104 kg moving at 3.00 m/s collides and couples with two coupled railroad cars , each of the same mass as the single car and moving in the same direction at 1.20 m/s .(a) What is the speed of the three coupled cars after the collision ?
(b) How much kinetic energy is lost in the collision ?
Physics Force & Laws Of Motion Level: High School
A rifle with a weight of 20 N fires a 5.0 g bullet with a speed of 280 m/sa. Find the recoil speed of the rifle
b. If a 700 N man holds the rifle firmly against his shoulder , find the recoil speed of the man and rifle .
Physics Force & Laws Of Motion Level: High School
A 2.80 kg steel ball strikes a wall with a speed of 10.0 m/s at an angle of 60.0 degree with the surface . It bounces off with the same speed and angle . If the ball is in contact with the wall for 0.180 s , What is the average force exerted on the ball by the wall ?
Physics Measurements Level: High School
(a)A student performed the ball drop experiment , measuring the acceleration of an object due to gravity five times . Her results for the trails were 9.7 , 9.8 , 10.0 , 9.9 and 9.8 all in units m/s^2 . What is the best estimate and uncertainly based on her measurement ?(b) The student is told that the accepted value of the acceleration due to gravity in San Diego is 9.81 m/s^2 . What is the discrepancy between her best estimate and the accepted value ? Do you think it is significant ?
Physics Kinematics Level: High School
In stunts for a new movie . In one scene the writers want a car to jump across the chasm between two cliffs . The car driving along a horizontal road when it goes over one cliff . The car is to travel through the air from one cliff to another , lower cliff . The higher cliff is 900 meters above the bottom of the chasm . The movie makers want to know the minimum difference in height between the upper road and lower road . So that the car does not fall into the chasm . They have not select a location so they want an expression for the difference in height between the upper road the lower road , h , in terms of the car’s mass , m , the width of the chasm , w , and the maximum road speed of the car , v (the maximum speed with which it can leave the upper cliff). The stunt director will plug in the actual numbers after the location is selected .
Physics Work,Power & Energy Level: High School
Calculate(a) the escape velocity of a rocket off the earth’s surface and
(b) the escape velocity of a rocket of the moon assume g at earth’s surface to be 9.81 m/s 2 and 5 at the moon surface 1.67 m/s^2 hint use work-energy theorem .
Physics Work,Power & Energy Level: High School
Calculate(a) the work that a student must do in order to carry a 25.0 kg backpack up a hill of height (40.0 meters)
(b) calculate the work done by gravity
(c) calculate the net work done the back pack .
Assume climber s motion is smooth with no acceleration in climbing up the hill .
Physics Force & Laws Of Motion Level: High School
Consider a rocket consumes 12 tons of fuel per second ; which it exhausts at 6500 ft/s . Calculate the thrust (upward force) exerted on the rocket . Compute force in pounds .
Physics Force & Laws Of Motion Level: High School
A 75 kg box in pulled up a ramp 25 meter long and is 6 meter high by a constant force of 150N . If the box starts from the rest and has a speed of 5.0 m/s at the top . Calculate the force of friction between the box and the ramp . Compute in MKS system .
Physics Gravitation Level: High School
A small asteroid begins falling towards the Earth from the Asteroid belt between the planets Mars and Jupiter (average distance from Earth = 3 AU where 1 AU = 1.5 x 10(8th) km) . Neglecting the gravitational force of the other planets and the Sun , what would be the maximum velocity (km/s) of the asteroid when it strikes the Earth’s surface ?
Physics Kinematics Level: High School
For an object to orbit the Earth , it must travel far enough horizontally such that if falls vertically at the same rates that the Earth’s surface is curving away from its horizontal path , about 5 meters vertically for each 8000 meters traveled horizontally . What would be the corresponding speed in kilometers per hour ?
Physics Heat & Thermodynamics Level: High School
An ice tray containing 150 g of water at 30 degree C, is placed in a freezer at -5 degrees C . How much energy (J) must be removed from the water to lower its temperature to the freezing point ? How much total energy (J) must be removed from the water for it to reach the same temperature as the freezer ? ( The specific heat , s , for the liquid water is 4.18 J/g . degrees C and for water ice is 2.05 J/g . degree C ; the heat of fusion for water is 334 J/g and the heat of vaporization is 2256 J/g ).
Physics Heat & Thermodynamics Level: High School
A one cubic centimeter cujbe of iron and one cubic centimeter of water are both heated to 100 degrees C . Each is transferred separately into beakers each containing 100 grams of water at 10 degree C . Explain which beaker of water would reach a higher temperature , the one to which iron had been transferred or the one to which the water had been transferred .
Physics Heat & Thermodynamics Level: High School
What is the ratio of the average kinetic energies of the two types of molecule ?