Physics Problems?

Question

These questions are to put on my in class notecard for my physics final as an example. Any help would be greatly appreciated!!!!!

A marble rolls off a 1.10 m high table with a speed of 2.5 m/s
a. how long in air??
b. distance traveled horozontially

Carl pulls a cart with a 65 N force above the horozontial
a. calculate horozontial and vertical components
b. if the cart moves 11.5 m, how much work does carl do?

Henry pulls a .45 kg toy with a X direction applied force of 3.2 N. Moves with a constant velocity.
a. net force in Y direction
b. calculate normal force
c. net force in x direction
d. force of friction
e. calculate coefficient of friction

Thanks!!!!!!! This will be of extrodinary help

Answer 1

The marble has only horizontal speed when it leaves the table so the horizontal motion is
x(t)=2.5*t

the vertical is
y(t)=1.1-.5*9.8*t^2

the flight time can be computed by finding t when y(t)=0, taking the positive of two roots
t=sqrt(1.1*2/9.8)

then x(t) when the marble hits the ground by plugging in the t of flight time.

For Carl and the cart, was there an angle from horizontal that Carl applied the force?

Call the angle th.

horizontal=65*cos(th)
Vertical=65*sin(th)
(this also works if there is no angle since sin(0)=0 and cos(0)=1)

the work is the horizontal times the distance
65*cos(th)*11.5

For Henry and the toy, since the toy moves with constant velocity the x direction force is equal to the normal force times the coefficient of friction. This is also equal to the force of friction. The net force in the x direction is zero since it is constant velocity there is no acceleration and F=m*a

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