Mechanics Question

[nid404]

Where does the 6cos60 come from
OMGGGG I DONT GETTT IT.

brain has shutdown.

6cos60 is the same as 6sin30

[elemis]

The 6 N force makes an angle of 60 degrees with the y axis. I used this 60 degrees when resolving in the Y DIRECTION.

[Dania]

Asif

I keep getting a tension of 8.32N when in fact I need to get 3N. I think I'm resolving the forces incorrectly, can someone please draw it out for me, and solve the question.

[nid404]

10 mins

[nid404]

attached

[elemis]

6cos60 is the same as 6sin30

Yeah, I prefer using cosine instead of sine. I'm biased that way

[nid404]

Yeah, I prefer using cosine instead of sine. I'm biased that way

Racist

[elemis]

Racist

wtv

[Deadly_king]

attached

Quite long but good

You could have resolved the weight P along the line of the string PS. But first you need to find the angles of the triangle APS.

T = 5cos 53.1 = 3.0N

Am sure this method will make Ari happy

[nid404]

hahaha

yup deadly king, that's one way to go abt it 

[elemis]

Am sure this method will make Ari happy

This wasnt my question smarty pants

[Deadly_king]

hahaha

yup deadly king, that's one way to go abt it 

Hats off to you though.....you were faster since you started earlier

@ Ari : I know .......but I used cosine and that's what you prefer, right?

[Dania]

Refer to the attachment, thanks

[nid404]

in the first part you found v=5m/s

for the second part, acceleration, t seconds after passing through A is given by (10-3t)
at t=0, v=5m/s

v=10t-0.15t²+C

substituting t=0 and v=5

you get c=+5

[Dania]

A ball is projected from a point O on the edge of a vertical cliff. The horizontal and vertically upward components of the initial velocity are 7ms^-1 and 21ms^-1 respectively. At the time t seconds after the projection the ball is at the point (x,y) referred to horizontal and vertically upward axes through O. Air resistance may be neglected.

(i) Express x and y in terms of t, and hence show that y= 3x- 0.1x²

The ball hits the sea at a point which is 25m below the level of O.

(ii) Find the horizontal distance between the cliff and the point where the ball hits the sea.