Question

1. If x+y = 6 and 2x+8y = 9, then what is x?

2. A distant object reverses its direction from +21.3 km/h to -20.5 km/h over 2.34 years. Find its average acceleration in m/s2 during this interval.

3. An ant has the following initial coordinates xintial = -5.0m, yinitial = 8.0m. If the ant relocates to the coordinates xfinal = 3.0m, yfinal = 0.0m in 24 seconds, what is the magnitude of its displacement?

4. Find the minimum coefficient of static friction necessary to allow an object to stay on rotating surface without slipping. Consider the radius of rotation to be 0.175m and the period to be 1.57s.

5. A small pebble is propelled by a contraption that exerts an 82.6 N-force over a distance of 0.828m. If the pebble's mas sis 72.5 grams, what velocity does it have at the end of acceleration?

6. Younger sister (41 kg) coasts on a massless inflated tube at a constant velocity of 1.6 m/s. Olrder sister (74 kg) gains on her at a velocity of 4.9m/s and hops on the tube. How fast do they coast afterwards?

7. A force F is applied to a box of mass M, as shown in the figure below. Express normal force algebraically in terms of box's weight, angle and force F.

Answer 1

Solution:

1) Given,

............ (1)

.,..... (2)

We can solve for using substitution method.

From eq. (1), we have

  

  

Substituting for in eq. (2), we have