The sum of the two vectors in A, B, and C is equal to the sum of the two vectors above the line. The sum of the two vectors in D isn't.
Answer:
10.2 metres
Explanation:
Given that a ball is projected at an initial speed of 20.0 meter per second making an angle of 45.0 with horizontal. What is the maximum height it will reach?
Solution
To get the maximum height, let us use the formula
V^2 = U^2 sin^2ø - 2gH
At maximum height V = 0
U^2 sin^2ø = 2gH
Substitute all the parameters into the formula
20^2 ( sin 45 )^2 = 2 × 9.8 × H
400 × 0.5 = 19.6 H
Make H the subject of formula
H = 200 / 19.6
H = 10.204 metres.
Therefore, the maximum height reached by the projected ball is 10.2 metres.
Answer
D. The average speed is 2.5 meters/second, and the average velocity is 0 meters/second.
The difference between speed and velocity is that, speed is a scalar quantity while velocity is a vector quantity.
Average speed = total distance/Total time
= (150 + 150) / (2×60)
= 300/120
= 2.5 m/s
Average velocity = Total displacement/ Total time
= (150 + -150) / (2 × 60)
= 0/120
= 0 m/s
Answer:
Plenum cabling
Explanation
As the plenum cabling are fire resistent so it will not cause the toxic components in case of fire.
I. Positive acceleration increases velocity. Negative acceleration decreases velocity. runner A sped up until the finish line and then slowed to a stop.
ii. Zero a acceleration implies a constant, unchanging velocity not a zero velocity. runner B achieved some velocity prior to 8s and is moving and must slow down to reach a stop.
iii. None. No aspects of this reasoning are correct. Everything she says is wrong. See iv for what/why.
iv. The sign on acceleration denotes the direction of *change in velocity* not change in direction. The sign on velocity can denote change in direction but only “forward” or “reverse” along a particular path. Cardinal direction is not indicated, generally, by the sign on velocity. It may correspond to North/South situationally but it is not an built-in feature of velocity and its sign. For example, if you are traveling with positive velocity and turn left to continue your journey you still have a positive velocity in the new direction. In fact, if you turn left again, traveling in the opposite direction as the one you started with your velocity would still be positive… in the new direction. The velocity relative to original direction could be said to be negative but that would be a confusing way to describe a journey. Maybe if you stopped the vehicle and moved in reverse, you could meaningfully say velocity was negative.
