Answer
(C).
When there is an angle between the two directions, the cosine of the angle must be considered.
Step by step Solution
The work done by a force is defined as the product of the force and the distance traveled in the direction of motion.
The first answer "Only the component of the force perpendicular to the motion is used to calculate the work" is wrong because, the force perpendicular to motion does no work.
The second choice "If the force acts in the same direction as the motion, then no work is done" is wrong because the work in the direction of the force is
.
Fourth answer "A force at a right angle to the motion requires the use of the sine of the angle" is wrong because the
meaning that there is no work done in the direction perpendicular to the motion.
The third answer" When there is an angle between the two directions, the cosine of the angle must be considered." is correct because the work is calculated using the force in the direction of the motion. The magnitude of this force is 
Answer:
time taken by the wave to reach the person is 0.2 s
Explanation:
As we know that the speed of the wave is given as

here we know that the wavelength of the wave is


now speed of the wave is given as


Now time taken by the wave to reach 5 m distance is



Answer:
PAPER CLIPS ON NOSE OF A PAPER AIRPLANE
Purpose: To determine if the number of paperclips on the nose of a paper airplane affects the velocity and speed, measured in meters per seconds.
Make a Hypothesis Based on the Learning Thus Far: If the number of paperclips on the nose of a paper airplane increases, then the speed will _increase______ (increase, decrease, stay the same) in a __linear_______ (linear, exponential, logarithmic) mathematical relationship, and the velocity will (increase, decrease, stay the same) in a __exponential____ (linear, exponential, logarithmic) mathematical relationship. (Fill in the appropriate words for your hypothesis.)
Pictures: Insert at least 3 pictures of yourself conducting the experiment into this lab report. At least 2 pictures must show your face as you conduct the investigation. You may need to ask someone to help take these photos.
Explanation:
The answer might be B because the value is negative, and negative could mean slowing down.