# Homework Help: Vectors and kinematics

1. Dec 13, 2007

### sabah

can someone please help me with these questionss... i have exam this week and i really need to know hwo to solve these problems. please... thank you and ya.. i do have the answers for it but i just cant get it when i try to solve it these problems are from my mid-term exam

(1) if B is added to A, the resultant has a x-component of 6 and a y-component of 1. if B is subtracted from A, the resultant vector has a x-component of -4 and a y component of 7. what is the magnitude of A?

(2) A ball is shot straight up from the surface of the earth with an initial speed. neglect any effects due to air resistance, find the intial speed of the ball if the ball was in the air for 2 seconds?

(3) a crankshaft of radius 0.3m rotates at a speed of 1.2 m/s. though what angle does it travel in 1/2 minute.

(4) a bullet is fired with a horizontal velocity in the positive x direction from the top of an 80 m high cliff. the bullet strikes the ground 1330 m from the base of the cliff. find the initial speed of the bullet.

(5) a 5.0 kg object is suspended by a string whose mass is negligible from the ceiling of an evelator that is acceletaring downward at 2.6 m/s square. what is the tension in the string?

(6) a block is pushed up a frictionless 30 degree inclined by an applied force. if F=25 N and M=3.0 kg, what is the magnitude of the resulting acceleration of the block?

2. Dec 13, 2007

Hi,