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luis00
Oct 7, 2010, 08:00 PM
1) Find the net force (in Newton) required to accelerate a 110 kg bike and rider from rest to a final velocity of 22.7 m/s in 10 seconds. Ignore any friction.

Since f=ma, is it 110(22.7)=2497 N and then do I divide that by 10 seconds?

2) A car is slides down an icy driveway that slopes at an angle of 10 degrees. What is the acceleration of the car?
I don't know how I would solve this one. Since the motion is horizontal is it (cos 10) but that doesn't give me acceleration.

luis00
Oct 7, 2010, 08:04 PM
Please ignore question 2

Unknown008
Oct 8, 2010, 01:02 AM
In F = ma, the a is the acceleration, not the speed.

You need to first use:

v = u + at

To find the value of a.
v is the final velocity,
u the initial velocity and
t is the time.

Care to try it again? :)

luis00
Oct 8, 2010, 11:59 AM
so the acceleration is 2.27, this is what I did
110(2.27)=249.7 N
correct?
Thanks!

Unknown008
Oct 8, 2010, 12:11 PM
Correct! :) Well done.