A ball is thrown upward at time t=0 from the ground with an initial velocity of 18 m/s (~ 40 mph). Assume that g = 10 m/s2. Time to reach apex 18/10 = 1.8
Time x 2 = 3.6
Great height reached by ball – (Velocity)(time)+(-5)(time^2) 18x1.8+(-5)(1.8^2)=16.2

A model rocket accelerates upward from the ground with a constant acceleration, reaching a height of 63 m in 8 s. * Speed at height 63 - 2x63/8 = answer What is the acceleration= answer/8 *

If you were to drop a rock from a tall building, assuming that it had not yet hit the ground, and neglecting air resistance, after 5.5 s; * How fast? 5.5x10
* How far? Half gravity = 5x5.5^2
*
A 1200 kg racing car accelerates from rest at a constant rate and covers a distance of 400 m in 10 s. What is the car's acceleration? (in m/s2) 400/10 = 40/10 = 4x2 = 8

If you throw a ball at 100m/s how long does it take to stop?

A ball is thrown downwards from a tall building at 5m/s. which statement is true after it is released?

*

A crate (80 kg) is hung in an elevator by a cord rated to withstand a tension of 1200 N. The elevator starts at rest and begins moving upwards until the cord holding the crate breaks. What was the acceleration of the elevator when the cord broke? Assume g = 10 m/s2

Top of Form
(T1R + W1E)/ mass |
Bottom of Form

Block 1 (4 kg) is located on the surface of a table. A hand pushes horizontally to the right on block 1 with a normal force of 16 N. On a sheet of paper, draw the free body diagram for block 1 using the two-subscript notation from class. After completing the free body diagram, enter below each force and its x & y-components. Remember that the x-component is the "i" component and the y-component is the "j" component.

FORCES on BLOCK 1
Weight force on block 1 by Earth
W1E = 0 i + -40 j N

Normal force on block 1 by Surface
N1S = 0 i + 40 j N

Normal force on block 1 by Hand
N1H = 16 i + 0 j N
| You are correct. Computer's...

...A1 Studying force of friction
Objective
To investigate the effect on friction of the following factors:
1. normalforce that presses the two surfaces together
2. materials that the two surfaces are made of
3. area in contact of the two surfaces
Apparatus
Rectangular wooden block
Wooden plank
Glass plate
Plastic plate
String
Scissors
Jack
Spring balance
Electronic balance
Half-meter rule
Retort stand and clamp
G-clamp
Trolley[pic]2
Standard weights (100g)[pic]5
Theory
Frictional forces act along the common surfaces between two bodies in contact so as to resist the relative motion of the two bodies. The frictions involved form an action-reaction pair.
A horizontal force F is applied to the wooden plank. As the plank is at rest, the friction force[pic] is equal to F and directs to the opposite side to resist the motion. The friction is static as there is no motion.
If F is increased, [pic]will also increase until it reaches the limiting static friction[pic]. Once the body starts to move, the frictional force would fall to a smaller value[pic], which remains constant even the applied force F is increased further.
In this experiment, the effects of the normalforce, the materials of the surfaces and the contacting areas on [pic] and [pic] are to be investigated.
Procedure
1. The mass and...

...SPH4U: Forces – Context Rich Problems
I do not have answers to these problems, and I haven’t thought about how to solve them. They are all fairly challenging and fair game for a test question. Work with friends on them, explain your solutions and convince yourselves that you understand the problems. I can’t tell you if you are right - I just don’t know!
1. Tension, Weight, Friction: You are taking advantage of an early snow to go sledding. After a long afternoon of going up and down hills with your sled, you decide it is time to go home. You are thankful that you can pull your sled without climbing any more hills. As you are walking home, dragging the sled behind you by a rope fastened to the front of the sled, you wonder what the coefficient of friction of the snow on the sled is. You estimate that you are pulling on the rope with a 2 pound force, that the sled weighs 10 pounds, and that the rope makes an angle of 25 degrees to the level ground
2. Tension, Weight: You are part of a team to help design the atrium of a new building. Your boss, the manager of the project, wants to suspend a 20-lb sculpture high over the room by hanging it from the ceiling using thin, clear fishing line (string) so that it will be difficult to see how the sculpture is held up. The only place to fasten the fishing line is to a wooden beam which runs around the edge of the room at the ceiling. The fishing line that she wants to use will hold 20 lbs....

...DIMENSIONAL FORCE SYSTEM
The first step in solving three-dimensional equilibrium problems, as in the case of two dimensions, is to draw a free-body diagram of the body (or group of bodies considered as a system)..
The reactive forces and couple moments acting at various types of supports and connections, when the members are viewed in three dimensions, are listed in Table 5–2. It is important to recognize the symbols used to represent each of these supports and to understand clearly how the forces and couple moments are developed by each support. As in the two-dimensional case, a force is developed by a support that restricts the translation of the attached member, whereas a couple moment is developed when rotation of the attached member is prevented. For example, in Table 5–2, item (4), the ball-and-socket joint prevents any translation of the connecting member; therefore, a force must act on the member at the point of connection. This force has three components having unknown magnitudes, FxFyFz Provided these components are known, one can obtain the magnitude of force. and the force’s orientation defined by the coordinate direction angles Eqs. 2–7.* Since the connecting member is allowed to rotate freely about any axis, no couple moment is resisted by a ball-and-socket joint. It should be noted that the single bearing...

...page essay
“How does Motion and Forces help your everyday life?”
All your life, forces has been acting on you even though you probably didn’t notice it. When you use your pencil, type, walk, or even when your doing something your using force. Those were a few examples of everyday life because, that’s what a force is “everyday life”. Everyday you use force to make your life easier.
The correct definition of “Force” is a push or a pull. I’ve always remembered that. For an example, when your doing homework you use a force on your pen or pencil because you push and pull it across the paper. Sometime two forces act on something at the same time, that’s called net force. If two people were pushing a shopping cart and they were pushing in the same direction, you would add the two forces together.
Net force is an unbalanced force, an unbalanced force is a force that changes the object’s motion or causes it to accelerate. Something else can happen if two forces move in one direction. If one force is more powerful then the other, they will not balance out to zero net force because , one force is stronger than the other, so the weak force is not strong enough to completely...

... 4. A 75 kg painter stands on a uniform 5.0 m board of mass 16 kg supported horizontally by two ladders. Find the forces exerted by each ladder on the board.
FR = 593N, FL = 299N
5. The diagram shows a horizontal beam of negligible mass. The wall exerts a 42.0 N horizontal force on the lever. Find the weight of the load.
16.1 N
6. A uniform 3.0 kg shelf of width 0.50 m is supported by a bracket, as shown in the diagram below. What force does the bracket exert on the shelf?
48 N
7. The diagram shows the forces acting on a massless ladder resting on the floor and a frictionless slope. As a person walks up the stationary ladder, what happens to the magnitude of the forces FN1 and FN2?
B
8. A uniform 350 kg beam of length 4.2 m is held stationary by a horizontal cable. The cable is attached to a point on the beam 3.0 m from the hinge.
a) Draw and label a free body diagram showing the forces on the beam.
[pic]
b) If the maximum tension the cable can withstand is 1.3 ×104N, what maximum mass, m, can be suspended from the end of the beam?
950 kg
9. A uniform 4.8 m long ladder of mass 16 kg leans against a frictionless vertical wall as shown in the diagram below. What minimum force of friction is...

...1. Two ropes are attached to a wagon, one horizontal to the west with a tension force of 30 N, and the other east and at an angle of 30° northward and a tension force of 40 N. Find the components of the net force on the cart. Show all your work.
Answer:
Horizontal Net Force = 40sin(30) – 30
Horizontal Net Force = -10
Vertical Net Force = 40cos(30)
Vertical Net Force = 34.6
Use the Pythagorean theorem = a^2+b^2=c^2
Resultant Force = (-102) + (34.62) = C2 = 33.1 N at 30o
(9 points)
Score
2. A 2.0 kg block rests on a level surface. The coefficient of static friction is µs = 0.60, and the coefficient of kinetic friction is µk = 0.40. A horizontal force, F, is applied to the block. As F is increased, the block begins moving. Describe how the force of friction varies as F increases from the moment the block is at rest to when it begins moving. Indicate how you could determine the force of friction at each value of F―before the block starts moving, at the point it starts moving, and after it is moving. Show your work.
Answer:
U=Ff/Fn
u=the coefficient of friction
Ff= Force of friction
Fn= normalforce
9.8x2=19.6N (normalforce)
U=Ff/19.6N
static friction is 0.60
0.60=Ff/19.6N 0.40=Ff/19.6N...