問題一覧
1
After reaching the finish line 100 m. from the starting line, runner A moves 5 m. beyond the finish line and then goes back to meet runner B. When they meet, runner B is still 10 m. away from the finish line. What is the net displacement of runner A?
90 m. to the right of the starting line
2
A 10 kg mass is held 1.0 m above a table for 25 seconds. How much work is done during that period?
0 Joules
3
The force of attraction between 2 identical bodies of 1 kg mass and separated distance of 1 meter.
6.67 x 10^-11 newtons
4
Uniform circular motion involves:
change in direction but not change in speed
5
The tendency of a body to remain at rest or in motion unless acted upon by an external unbalanced force:
inertia
6
A boy spins vertically a marble attached to a string. At which point is the tension greatest?
at the lowest point
7
A horse exerts a force of 3,000 N while pulling a cart for 6 km. How much work does the horse do? Give your answer in mega joules
18 MJ
8
In an activity, Joel observed that there are two sets of circular waves spreading out across the surface of the water in the tank. This shows:
diffraction
9
What has to happen for an object to maintain a circular path?
the speed must be kept constant
10
Calculate the rate of acceleration for a runner who reaches a speed of 2 m/s in 10 seconds. a. C. d.
0.2 m/s^2
11
Which of the following is true?
The potential energy for I is greater than the kinetic energy for ll.
12
Which of the following is not true about a projectile fired at 196 m/s at an angle of 30 degrees with the horizontal? All of the
It has zero acceleration when it reaches maximum height.
13
According to the Law of Conservation of Momentum, the total momentum of a system before a collision is the total momentum of the system after collision.
equal to
14
When an object falls freely, its acceleration is:
constant
15
Which scientist would have most likely used phrases "equal areas", "planetary period", and "elliptic foci”?
Johannes Kepler
16
In the previous problem, what is the weight of the lift?
16660 N
17
When a stone is thrown up into the air, at what point in its flight is the velocity decreasing?
before it reaches the highest point
18
The term used to describe the constant random motion of colloidal particles.
Brownian movement
19
Which of the following is not true about a projectile fired at 196 m/s at an angle of 30 degrees with the horizontal?
Velocity decreases to zero when it reaches maximum height then increases further on.
20
The efficiency of a machine is:
always less than 100%
21
A can of biscuit is usually opened with a spoon. When used this way the spoon is an example of a lever. Which statement best describes the positions of the effort, fulcrum and resistance?
The fulcrum is between the resistance and effort.
22
A quantity having both magnitude and direction is called a vector quantity. Which below can be represented by a vector quantity?
displacement
23
To calculate the gravitational force between two objects, you do net need to know the:
acceleration of both objects
24
In the previous problem, what is the maximum possible magnitude of the resultant vector?
14 N
25
A bullet of mass 0.01 kg is fired into suspended wooden block of mass 0.29 kg at 120 meters/second. If the bullet remains in the block after the collision, what is the final velocity of the bullet and block?
4 m/s
26
When an object moves at constant velocity, the net force acting on it is
zero
27
Which of the following is not a fundamental physical quantity?
velocity
28
For a ball thrown vertically upward, the time it takes to reach its maximum height is_the time it takes to go down.
equal to
29
Which of the following is not a unit of pressure?
Joule
30
A rocket coasting along in space at some speed, V, fires Its engines thus doubling its speed. At the same time, It unloads some cargo reducing its mass to half Its value. In the process, Its kinetic energy is a,
doubled
31
What is the maximum height that the ball will reach?
490 m
32
The first law of thermodynamics states that:
While the kind of energy in a closed system can change, the total amount cannot.
33
When will the ball reach a speed of 49 m/s?
after 5s and 15 s
34
What is the resultant of this system?
100 N located on the 4th quadrant
35
When a long, straight wooden pole is partly submerged in water, the pole looks bent. What explains this phenomenon?
refraction
36
A race car emits a distinctive roar when it passes you and slowly the frequency decreases as it moves away, it exhibits:
Doppler effect
37
What can you say about the motion of a stone thrown vertically upwards? a. b. C. d.
The stone increases speed as it falls from maximum height at constant acceleration.
38
The statements below comprises Keplers' Laws of Planetary Motion except for:
The periods of the planet are proportional to 3/2 powers of the major axis lengths of their orbits
39
A lift of mass 1700 kg moves upwards with an acceleration of 1.5 m/s?. What is the upward force acting on the lift?
2550 N
40
Which is true of sound waves?
both a and b
41
Two forces, one 40 Newton, the other 26 Newton act on a body. The directions of the forces are unknown. What is the minimum possible magnitude of the resultant vector
14 N