A duck flies 60 m in 6 seconds what is the ducks speed? Show your work plz
1 answer:
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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
Explanation :
It is given that,
Mass of the car, m = 1000 kg
Force applied by the motor,
The static and dynamic friction coefficient is,
Let a is the acceleration of the car. Since, the car is in motion, the coefficient of sliding friction can be used. At equilibrium,
So, the acceleration of the car is . Hence, this is the required solution.