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A motorboat starting from a dead stop accelerates at a constant 1.7 m/s2 for 2.5 s, then very rapidly roars up to 4.4 m/s2 and holds it constant for 4.0 s. What is its average acceleration over the first 4.9 s of motion?
What is its speed after 6.5 s?
Next the boat decelerates to a stop in 19.0 s at a constant rate. What is the boat's acceleration during this last portion of the trip?
In the vertical jump, an athlete starts from a crouch and jumps upward as high as possible. Even the best athletes spend little more than 1.00 s in the air (their “hang time”). Treat the athlete as a particle and let Ymax be his maximum height above the floor. To explain why he seems to hang in the air, calculate the ratio of the time he is above Ymax/2 to the time it takes him to go from the floor to that height. Ignore air resistance.
The acceleration of a motorcycle is given by ax(t)=At-Bt2, where A=1.50m/s3 and B=0.12m/s4 . The motorcycle is at rest at the origin at time t=0.
a. Find its position and velocity as a function of time.
b. Calculate the maximum Velocity
From an elevated point A, a stone is projected vertically upward. When the stone reaches a distance h below A, its velocity is double what it was at height h below A. Show that the greatest height obtained by the stone above A is 5h/3.
Explain buoyancy force.
Two springs on a bar are connected to earth as shown opposite: D1 and D2 are the Hook's constants of the two springs. The beam is mounted massless and rotatable at point E. a) By which lengths XI and .T2 do the springs expand with the spring constants Dl 500N / m, D2 300N / m, if the force F 100N acts as shown? b) At what angle does the bar incline to the horizontal?
I could not add picture..... Sorry
When you riding in a commercial airplane, it appears that the plane is at rest and the Earth
is moving underneath you. Is this point of view valid? Discuss briefly,
What is the absolute air pressure of a ballon inflated to 11.5 lb/in.^2
A wheel is spinning at 5.38 rad/s, and has an angular momentum of 4.05 kg.m2/s. What is its moment of inertia?
Write maximum range in projectile motion.
