Homework Statement
Find a positive number such that the sum of the square of the number and its reciprocal is a minimum.
Homework Equations
The Attempt at a Solution
y=X^2+(1/X^2)
Derivative=2x-2x^(-3)
0=2x-2x^3
2/x^3=2x
2=2x^4
1=x^4
x=1
The answer I got was 1 but I'm...
Homework Statement
Find the applied force for a object if the coefficient of kinetic friction equals 0.30 and the acceleration equals 5m/s^2. The applied force makes a 40 degree angle with the horizontal. The mass of the object is 10kg.
Homework Equations
Fnet=ma
The Attempt at a...
Homework Statement
Dave and Andrew are racing. Dave running at a constant speed of 20m/s is passed by Andrew. 2.0s after Andrew passes, Dave accelerates at 1.0m/s^2 until he catches up with Andrew 25s later. What is Andrew's velocity (he does not accelerate)?
Homework Equations...
Homework Statement
If you can hurl a ball so that its initial speed is 30m/s, what is the widest river you can throw it across?
Homework Equations
The range equations,
t=2(vi)(sintheta)/g
d=visin2theta/g
The Attempt at a Solution
I know you have to use components so what I...
Homework Statement
A person jumps 8.9m. The person's takeoff speed was 15m/s. What is the angle relative to the ground at takeoff?
Homework Equations
The Attempt at a Solution
I found t using the kinematic formula to be 0.5s using the formula. d=vit+1/2at^2. Can someone tell...
Homework Statement
If a ball is thrown upwards and lands in the same spot, would it take longer to reach max height or drop back down from the max height? Also use air resistance.
Homework Equations
The Attempt at a Solution
I believe that it would take longer for the object to...