Find the angle made by the vector 4i+3j+5k on x axis

Explanation:

The magnitude of resultant vector in three dimension

If vector A = 4i + 3j + 5k

The calculated magnitude  | A | = = = 7

If the angle formed with x-axis by this vector is α

Then cosα = x-component of vector divided by its magnitude

or cosα = = 0.57

and angle α = 35° approx

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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d) physical means can be used to separate the components of air.