1. Galileo tries to measure g.
Galileo tried to measure the acceleration of gravity by rolling balls down successively steeper inclines.
Since he lacked an precise time piece, he used a water clock to measure the time. (number of drops) The inclines served to increase the time of dropping so that he could measure accurately with his water clock.
By moving the bell gates to be equal times apart, he was able to show that distance is related to the square of time.
He showed that as the angle got steeper, the rate of acceleration increased and tried to predict what the rate would be for an angle of 90o.
Unfortunately, as the angle got to above 40o , the balls started to slide down the incline rather than rolling. This change in the frictional force prevented him from getting a value for g

2. Independent Motions
A boat is crossing a river which has a current of 8.00 m/s. If the velocity of the boat on a still lake is 5.00 m/s then:
A) What is the net velocity of the boat?
B) How long does it take the boat to cross a 120 m river?
C) How far downstream will the boat end up after crossing the river?

3. 80 km/h. What is the track velocity of the plane?
A plane is headed north at 350 km/h, when it encounters a wind from the west at
80 km/h. What is the track velocity of the plane? N q
The plane will travel at 359 km/h at 77.1o N of E.

4. A force of 350 N at 48o S of E and a force of 400 N at 56o S of W simultaneously act on a small cart.What is the net force on the cart?
48o
350
56o
400
What else needs to be done on this problem?
Find the net vector using Pythagorean theorem and find the angle for the net vector using tan-1.
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