Physics Kinematics Level: High School
Mechanics
Two brothers, Dustin and Parker, have a combined mass of 168 kg. At an ice skating rink , they stand close together on skates, at rest and facing each other, with a compressed spring between them. The spring is kept from pushing them apart because they are holding each other. When they release their arms, Dustin moves off in one direction at a speed of 0.90 m/s, while Parker moves off in the opposite direction at a speed of 1.2 m/s. Assuming that friction is negligible, find Dustin’s mass.a. 72 kg
b. 80 kg
c. 96 kg
d. 77 kg
e. 84 kg
Physics Alternating Current Level: High School
Mechanics
A 5.0 x 10^4 kg space probe is traveling at a speed of 11,000 m/s through deep space. Retrorockets are fired along the line of motion to reduce the probe’s speed. The retrorockets generate a force of 4.0 x 10^5 over a distance of 2500 km. What is the final speed of the probe?a. –3.38 x 10^3 J
b. zero J
c. 3.38 x 10^3 J
d. –345 J
e. 345 J
Physics Work,Power & Energy Level: High School
In the 1950's, an experimental train that had a mass of 23800 kg was powered across a level track by a jet engine that produced a thrust of 584000 N for a distance of 557 m. Find the work done on the train . Answer in units of J. Find the change in kinetic energy. Answer in units of J. Find the final kinetic energy of the train if it started from rest. Answer in units of J. Find the final seed of the train assuming no friction
Statistics Statistics Level: University
Using economic theory explain the rationale for having a fixed monthly tariff, as well as charges for each call, in the market for mobile phones.
Statistics Statistics Level: University
Baseball Controversy
In recent years a controversy has arisen in major league baseball. Some players have been accused of "doctoring" their bats to increase the distance the ball travels. However, a physics professor claims that the effect of doctoring, no matter how it is done, is negligible. A major league manager decides to test the professor's claim considering two different types of doctoring. He doctors two bats by inserting cork into one and rubber into another. He then selects five players on his team and has them each hit a ball with an un-doctored bat and with each of the doctored bats. The distances are measured and listed below. Distance Ball Travels (in feet)| Player | Un-doctored Bat | Bat with Cork | Bat with Rubber |
| 1. | 275 | 265 | 280 |
| 2. | 315 | 335 | 320 |
| 3. | 425 | 435 | 440 |
| 4. | 380 | 375 | 370 |
| 5. | 450 | 460 | 450 |
a.) Do these data provide sufficient evidence at a 5% level of significance to refute the professor's claim?
b.) Does our result indicate the need for any multiple comparison testing? Why? If yes, do it. Use α = 0.05). You must show all seven steps.
Physics Kinematics Level: High School
Mechanics
An elevator has a mass of 1170 kg and carries a maximum load of 652 kg. A constant frictional force of 3570 N retards its motion upward. The acceleration of gravity is 9.8 m/s/s. What must be the minimum power delivered by the motor to lift the elevator at a constant speed of 3.63 m/s? Answer in units of W. What power must the motor deliver at an instantaneous speed of 3.63 m/s if the elevator is designed to provide an upward acceleration of 0.718 m/s/s? Answer in units of W.
Physics Kinematics Level: High School
Mechanics
An elevator has a mass of 1170 kg and carries a maximum load of 652 kg. A constant frictional force of 3570 N retards its motion upward. The acceleration of gravity is 9.8 m/s/s. What must be the minimum power delivered by the motor to lift the elevator at a constant speed of 3.63 m/s? Answer in units of W. What power must the motor deliver at an instantaneous speed of 3.63 m/s if the elevator is designed to provide an upward acceleration of 0.718 m/s/s? Answer in units of W.Physics Kinematics Level: Middle School
Motion in 2D and 3D(Mechanics)
A stone is dropped from the top of a cliff. The splash it makes when striking the water below is heard 3.5 seconds later. How high is the cliff?
Physics Kinematics Level: High School
Motion in 2D and 3D(Mechanics)
A stone is dropped from the top of a cliff. The splash it makes when striking the water below is heard 3.5 seconds later. How high is the cliff?Mathematics Algebra Level: University
Do you think the current highway speed in Canada is appropriate? How would you decide whether or not it should be increased or decreased?Focus: Applying the marginalist principle to try to find an optimal speed limit for road traffic.
Mathematics Coordinate Geometry Level: High School
a ) Find the slope of any line parallel to the line through points (18, 14) and (10, 10).b ) Find the slope of any line perpendicular to the line through points (11, 3) and (9, 7).
Mathematics Coordinate Geometry Level: High School
Slope and the y intercept of a line.
Find the slope and the y-intercept.y = –7x + 3
Find the slope and y-intercept.
10x + 6y = –54
Mathematics Coordinate Geometry Level: High School
Drawing the graph of a line in the form y=mx + c where m is the slope of the graph and c is the y-axis intercept.
Graph y = -2x + 1.
Mathematics Coordinate Geometry Level: High School
Constant of variation of a line
If y varies directly with x, and y = 144 when x = 8, find the constant of variation k.
Mathematics Coordinate Geometry Level: High School
Slope of a line passing through two points.
Find the slope of the line passing through the points (2, 1) and (4, 7).Find the slope of the line passing through the points (3, -5) and (3, 1).
