Newton&39;s laws of motion PhO(5)

(A) 0 (B) v upwards (C) 2v upwards (D) v downwards (E) 2v downwards

14.(09.1)

Spaceship-A moves at velocity 40(Spaceship-B moves at 30 (Spaceship-B in the fixed coordinate system in the unit of km/s. A. 10xo+10yo D. 70xo+10yo

15. (07.13)

A rocket is launched vertically upward from ground and moves at a constant

acceleration of 19.6 m/slaunch. To escape, the astronauts must eject at least 3 seconds before the rocket hits the ground. Neglect air resistance. How long will the astronauts have before ejection? A. 45.5 s B. 34.5 s

16. (09.14)

Object-A is dropped from a height upward from the ground. Right before they collide in mid-air, the speed of A is twice the speed of B. Determine the height where the collision occurs. A. 2h/3 B. h/3

Key: ABCCB EBACA

xo+yo) km/s relative to a fixed coordinate system. xo-yo) km/s as seen by Spaceship-A. Find the velocity of B. 10xo+70yo

C. 10E. 10xo-10yo

C. 6.5 s D. 41.5 s h. At the same instant object-B is thrown vertically h/4 D. h/2 E. BEADD A

xo+10zo

E. 13.5 s 2. By accident, the engine is suddenly shut off 10 seconds after

C. 3h/4

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