Category Archives: Pressure and Force

Calculating the Force

A) You have a syringe as shown in the picture, which is filled with 10 ml of water.
The inner diameter of the main body of the syringe is 15.9 mm, and the inner
the diameter of the outlet is 1.2 mm. With how much force you have to press
the plunger for clearing the syringe for water within 10
Seconds? You can overlook the friction of the piston and the viscosity of the water.

B) Now attach a needle to the syringe, with a length of 25 mm and inner diameter
0.210 mm. If you press the plunger with the force 0.10 N, how long
will it take to empty the syringe? Now you can no longer ignore the viscosity
to the water, which is = 0.0010 Pas.

Calculating the Force

a) A ball of mass m = 0.10 kg is sent down into a ball path. The orbit consists of a quarter circle with radius r = 2.0 m. We ignore friction and air resistance. When the bullet is at its lowest point, it hits a box of mass M.

Show that the speed of the bullet is at its lowest point (just before it
hit the box), v0 is 6.3 m / s. Also find the normal force on the ball just before leaving the circular orbit.
b) When the ball leaves the circular orbit, it hits a box of mass
M = 1.0 kg. The box is sticky on the left side, so the ball gets stuck
to the box. The box is on a table. The friction number against the substrate for the composite body (box + sphere) is = 0.3. What will be the speed of the compound body right after the impact? How far does the body move after this shock? Disregard air resistance.