Question

If the 2.00 cm diameter inlet tube narrows to 1.00 cm in diameter, what is the pressure drop in the narrow section for the 2.16 m/s airflow in the 2.00 cm section? (Suppose the air density is 1.25 kg/m3.)

a. 20.3 Pa

b. 11.7 Pa

c. 45.7 Pa

d. 43.7 Pa

Two rigid objects, a ring and solid disc, have the same mass, radius and angular velocity. If the same braking torque is applied to each one, which takes longer to stop?

a. disco

b. more information is needed

c. both equally

d. aro

A uniform solid sphere rolls down a slope of height 3 m after starting from rest. To calculate your speed at the bottom of the tilt, one needs to know:

a. the mass and radius of the sphere.

b. the mass of the sphere.

c. the radius of the sphere.

d. no more than what is given in the problem.

Why do steam bubbles get larger in boiling water as they approach the surface?

a. Bubbles always get bigger after they form.

b. The pressure of the bubbles increases as they rise.

c. They just seem to get bigger, this being just an optical effect.

d. Water pressure decreases as the bubble rises to the surface.

A disc has a moment of inertia of 3.0 x 10-4 kg m2 and rotates with an angular velocity of 3.6 rad/s. What net torque should be applied to stop it in a time of 3.6 seconds?

a. 3.00E–4 N.M

b. 3.89E-4 N.m

c. 4.32E-4 N.m

d. 30.0E-4 N.m

A solid 2.50 kg mass sphere and a radius of 0.120 m is at rest at the top of a 15.0 0 sloping ramp, rolling down without slipping. The top end of the ramp is 1.20 m higher than the lower end. Find the total kinetic energy of the sphere when it reaches the end.

a. 29.4 J

b. 70.0 J

c. 47.9 J

d. 8.80 J

In a pool, a basketball is submerged at 1m deep, what happens to the thrust force (buoyant) exerted on the ball as you take it further to the bottom?

a. Decreases.

b. Increase.

c. It is impossible to determine.

d. It stays constant.

Two spheres, one hollow and one solid, rotate with the same angular velocity around an axis through its centers. Both spheres have the same mass and radius. Which sphere has the highest rotational kinetic energy?

a. the hollow sphere.

b. the solid sphere.

c. Mission impossible.

d. They have the same kinetic energy.

A porrist takes two batons and holds them in the middle at right angles to make an "X"-shaped solid. Each baton is 0.70 m long and each ball at the end is 0.10 kg. (Ignore the mass of the rods.) What is the moment of inertia of the "X" system if it rotates around the center through the axis perpendicular to both rods?

Select one:

a. 4.9E–2 kg.m²

b. 7.0E–3 kg.m²

c. 2.5E-2 kg.m2

d. 1.2E-2 kg.m2

Answer 1