An angle marking is like a meter stick marking. The marking of 1.2m on a meter stick only means an object is 1.2m long if the ob
1 answer:
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Answer:
(A) it's acceleration is negative but but it's velocity is positive
Explanation:
In the question it is given that begins to slow down so its speed is decreasing it is does not means that its speed is negative
For example let first the velocity of the car is 30 m/sec and when its velocity decreases it becomes 20 m/sec in 5 sec
So it is not negative at all
Now the acceleration is the rate of change of velocity
So acceleration is negative here
So option (a) will be the correct option
Answer:
Yes
Explanation:
The velocity measured by Jennifer and Johnny is
The actual velocity is
We can calculate the % error of the students measurement as follows:
Which is lower than the 2.5% maximum error required, so the two students will pass the test.
42) The sailboat travels east with velocity 
, while the current moves south with speed 
. Since the two velocities are perpendicular to each other, he resultant velocity will be given by the Pytagorean theorem:
and the direction is in between the two original directions, therefore south-east. So, the correct answer is
D) 42 mph southeast
43) Since the light moves by uniform motion, we can calculate the distance corresponding to one light year by using the basic relationship between velocity, space and time. In fact, we know the velocity:
and the time is one year, corresponding to:
therefore, the distance corresponding to one light year is:
Therefore, the correct answer is D.
44) For the purpose of the problem, we can assume that the light travels instantaneously from the flash to us (because the distances involved are very small), so the time between the flash and the thunder corresponds to the time it took for the sound to travel to us.
The speed of sound is
And since the time between the flash and the thunder is t=3 s, the distance is
Therefore, the correct answer is A) 3/5 mile.
and the direction is in between the two original directions, therefore south-east. So, the correct answer is
D) 42 mph southeast
43) Since the light moves by uniform motion, we can calculate the distance corresponding to one light year by using the basic relationship between velocity, space and time. In fact, we know the velocity:
and the time is one year, corresponding to:
therefore, the distance corresponding to one light year is:
Therefore, the correct answer is D.
44) For the purpose of the problem, we can assume that the light travels instantaneously from the flash to us (because the distances involved are very small), so the time between the flash and the thunder corresponds to the time it took for the sound to travel to us.
The speed of sound is
And since the time between the flash and the thunder is t=3 s, the distance is
Therefore, the correct answer is A) 3/5 mile.