1 . How fast (in rpm) must a centrifuge rotate if a particle 8.0 cm from the axi

Question

1. How fast (in rpm) must a centrifuge rotate if a particle 8.0 cm from the axis of rotation is to experience a centripetal acceleration of 500000 m/s2?
rpm

2. A dentist causes the bit of a high-speed drill to accelerate from an angular speed of 1.15 × 104 rad/s to an angular speed of 3.95 × 104 rad/s. In the process, the bit turns through 1.74 × 104 rad. Assuming a constant angular acceleration, how long would it take the bit to reach its maximum speed of 6.80 × 104 rad/s, starting from rest?
s

3. The pedals of a bicycle rotate in a circle with a diameter of 30 cm. What is the maximum torque a 70-kilogram rider can apply by putting all of her weight on one pedal?
N.m

4. A 90 kg scaffold is 7.00 m long. It is hanging with two wires, one from each end. A 400 kg box sits 1.50 m from the left end. What is the tension in the right hand side wire?(g = 9.8 m/s2)
Newtons

5. A 110 kg uniform beam is attached to a vertical wall at one end and is supported by a cable at the other end.
a) Calculate the magnitude of the vertical component of the force that the wall exerts on the left end of the beam if the angle between the cable and horizontal is = 49°.
N

6. A uniform ladder of mass (m) and length (L) leans against a frictionless wall, see figure. If the coefficient of static friction between the ladder and the ground is 0.38, what is the minimum angle () between the ladder and the floor at which the ladder will not slip?
degrees

7. A woman who weighs 436 N is leaning against a smooth vertical wall, as the drawing shows.
a) Find the force FN (directed perpendicular to the wall) exerted on her shoulder by the wall.
N

8. (b) Find the vertical component of the force exerted on her shoes by the ground.
N

9. (c) Find the horizontal component of the force exerted on her shoes by the ground.
N

10. A block of mass m = 2.10 kg is hanging from a massless cord that is wrapped around a pulley (mass = 7.00 kg) as shown in the figure. The cord does not slip relative to the pulley as the block falls. Find the magnitude of the tension in the cord. (moment of inertia of the pulley = ½Mr²)
N

Explanation / Answer

Solving 1st question

Centripetal accleration=w*w*r=500000

r=0.08 m

We got w=2500 rad/s =23873.2 rpm

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.