SelfTest: Dynamics in 1D and 2D Test #2
Suggested Time: 60 minutes
1. 
Two forces act at a single point as shown. What is the magnitude of the resulting force?


2. 
A force of 45 N is applied at an angle of 35° above the horizontal to pull a 21 kg crate across a floor as shown below. What is the normal force on the crate?


3.  A frictionless pulley is set up with
two hanging masses as shown below.
What is the tension in the right hand rope while the masses move freely?


4. 
Two masses are connected together by a rope and pulley on a frictionless inclined plane as shown.
When the system is released, what is the initial acceleration of the 21 kg mass?


5. 
A 15 kg block is pushed up a 35° incline. A friction force of 110 N exists between the block and the incline. What minimum force F, would be necessary to move the block up the incline at a constant speed?


6.  An 810 kg dragster is
being decelerated by a parachute at 2.5 m/s^{2}
as shown in the diagram.
What is the tension in the cord at this moment?


7.  The system of blocks
on a frictionless surface in the diagram below is accelerating at 2.0 m/s^{2}
.
What is the tension in the cord at X?


8. 
Which of the following graphs shows the relationship between acceleration and net force?


9.  A 15 kg block on a horizontal
surface has a 100 N force acting on it as shown.
What is the normal force?


10.  A 15 kg cart is
attached to a hanging 25 kg mass. Friction is negligible.
What is the acceleration of the 15 kg cart?


11.  A 15 kg block has a constant
acceleration of 2.2 m/s^{2}
down a 30° incline.
What is the magnitude of the friction force on the block?


12.  An 80 kg man stands on a spring scale while
accelerating upwards in an elevator. If the scale indicates that his
"weight" is 980 N, what is the magnitude of the acceleration of the
elevator in meters per second squared?


13.  4.0 kg model boat is pulled by two ropes. One has
a tension of 40 N directed at 45° north of east and the other 30 N at 37°
south of east. What is the magnitude of the resultant force acting on the
boat?


14. 
A high diver of mass 74.0 kg jumps off a board 9.00 m above the water. If his downward motion is stopped 2.50 s after he enters the water, what average upward force did the water exert on him?


15. 
A 2.50kg mass is observed to accelerate at 16.0 m/s^{2} in a direction 39.0^{0} north of east.
The force F_{2} acting on the mass has a magnitude of 25.2 N and is directed north. Determine the magnitude and direction of the force F_{1} acting on the mass.


16. 
The system shown below has an acceleration of magnitude 2.00
m/s^{2}. Assume the coefficients of kinetic friction between block and incline are the same for both inclines. Find (a) the coefficient of kinetic friction and (b) the tension in the string.


17. 
A 15.0 kg block is pushed up a 30 degree incline by a horizontally applied force of 150.0 N. The coefficient of friction between the surface and the block is 0.25. Find the acceleration of the block. (7 marks) 

18.  An 18 kg cart is connected to a 12
kg hanging block as shown. (Ignore friction.)
a) Draw and label a free body diagram for the 18 kg cart. (2 marks) b) What is the tension in the cord connecting the two carts? (5 marks) 

19. 
Two masses are connected by a light string over a frictionless massless pulley. There is a coefficient of friction of 0.27 between mass m_{1} and the horizontal surface. a) Draw and label a free body diagram showing the forces acting on mass m_{1}. (2 marks) b) What is the acceleration of mass m_{2 }? (5 marks) 

20.  A 35 N force applied at 21°
to the horizontal is used to pull a mass
as shown.
The coefficient of friction between the floor and the mass is 0.15. a) Draw and label a free body diagram showing the forces acting on the mass. (2 marks) b) What is the acceleration of the mass? (5 marks) 
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