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Unit 7 Forces Test
This will help you prepare for the Unit 7 test on Forces and Motion.
Question | Answer |
---|---|
The following table shows information about three different objects sitting on a bookshelf. Some data is missing from the table. Therefore, if object 2 has a height of 3 meters, what is its gravitational potential energy? | 176.4 J |
The motion of Usain Bolt running the 100 meters is which type of energy? | kinetic energy |
A child pushes a toy car down a hill. After 5 seconds, the car has a kinetic energy of 115 J and a gravitational potential energy of 30 J. Therefore, what is the car's mechanical energy at that time? | 145 J |
The ends of the wire are connected to the terminals of a battery, as shown in the image. When an electric current is in the wire, the compass needle moves to the right. Which of the following best explains why this happens? | The electric current produces a magnetic field, and this moves the magnet on the compass needle. |
Ashlea wants to start a Science Club that investigates the interactions between electrical energy and magnetism. What is the main process that this club will investigate? | electromagnetism |
Why is the friction force considered to be a contact force? | Friction acts in a direction opposite to the direction of an object's motion. |
The dotted lines in the following picture show orbital paths of objects. Which statement is true about all of the orbits shown? | The force of gravity is what holds each object in its orbit. |
A skydiver jumps out of a plane. She falls downward at a very fast speed. When she opens her parachute, she slows down. What force pulled the skydiver to the ground? | gravity |
Two charged objects are near each other, but they do not touch. Which process is possible? | charging by induction |
The bottom of a cloud gains a strong negative electric charge. A scientist observing a metal pole directly beneath the cloud determines that the top of the pole has a positive electric charge. Which of the following explains this observation? | The positive charges within the pole concentrate at the top of the pole to be near the negatively charged cloud bottom. |
Some of the materials for a laboratory experiment are copper wire, plastic tubing, and a pair of cotton gloves. Why is the copper wire the best electrical conductor in this group of materials? | Copper wire allows electric charges to flow easily through it. |
Landon has an idea to cut a bar magnet in half so that he can have one magnet with a north pole and one with a south pole. What is wrong with this idea? | It is impossible to create a magnet with only one magnetic pole. |
What is the net force on the soccer ball? | 50 N to the left |
A soccer player kicks a ball. According to Newton's 3rd Law of Motion, the player's foot exerts a force on the ball and the ball exerts a force on the foot as well. Therefore, why don't the forces cancel out to result in a net force of zero (balanced)? | The forces are exerted on different objects so they are not balanced forces. |
An atom loses an electron. What will happen when it approaches a positively-charged ion? | The ions will repel each other. |
Below is a diagram of a weight on a spring. When the weight is pulled down and then released, the spring compresses and expands. Each position indicates a different point in time. Therefore, which of the following statements is true? | The elastic potential energy of the spring at Position 2 is converted to kinetic energy. |
Three positions during the swing are identified as Position 1, Position 2, and Position 3. Ignoring the effects of friction and air resistance, at which point would the pendulum have the greatest amount of mechanical energy? | Mechanical energy does not change. |
What is the tendency of all objects to resist a change in motion? | inertia |
What unit of measure will fluctuate depending on the size of the planet you're on? | weight |
What causes Earth to behave like an enormous magnet? | Convection currents moving liquid iron in the outer core. |
Where is the magnetic north pole located? | Geographic South Pole |
Which atomic particle allows electricity to create magnetism and magnets to create electricity? | electron |
What is a coil of wire with an electric current, that produces a magnetic field? | solenoid |
What type of transformer will be found outside your homes on the power lines? | Step-Down transformer |
A Ferrari with a mass of 1,200 kg is traveling at a velocity of 40 m/s on the expressway. Using the formula below, calculate the kinetic energy for the Ferrrari. | 960,000 Joules |