Forces and the Laws of Motion - Physics Test 12/10/20
A rigid rod holder restaurant sign horizontally from the side of a building. The force due to gravity acting on the sign is 165 N with the angle between the sign and the rod being 50.0°. Ignoring the weight of the rod, what is the magnitude of the tension in the rod
(165 + 50.0) = 215 N
In object is at rest on an incline. The component of gravity acting downward in along the incline on the object is described as F g,x = +8.0 N. Which axis is pointing up the incline?
-x axis
A force of 5 N in a force of 15 N acting on an object can produce the following that forces except... A) 20 N B) 15 N C) 10 N D) 5 N
5 N
During a three-part circus stunt, a clown holds a ball. The clown then tosses the ball upward. After releasing it, the ball is caught a few moments later from above by another clown on a trapeze. Which set of data could represent the normal force exerted by the ground on the first clown during the stunt? The force due to gravity on the clown is 680 N and that on the ball is 20 N.
700 N, 705 N, 680 N
A force unit defined as the product of a mass unit and unit of
Acceleration
In an action reaction pair, the...
Action force and the reaction forces act on two different objects
The normal force...
Acts perpendicular to a surface
The Acceleration due to gravity A) is caused by Field Force B) has a magnitude of 9.81 m/s^2 at earths surface C) is represented by the symbol, a g
All of the above
Which of the following situation describes inertia? A) A stationary object is to resist being moved B) A moving object tends to resist a change in speed C) A moving object tends to resist a change in direction
All of the above
Two forces acting on an object. The magnitude of the net force acting on the object...
Cannot be determined from the given information
Lubricant decreases kinetic friction between services. The most likely reason it reduces kinetic friction is because the lubricant...
Changes the composition qualities of the surfaces in contact
For an object in contact with the given Serpas, the kinetic friction acting on the object...
Depends on the composition and qualities of the surfaces in contact
The coefficient of kinetic friction...
Depends on the composition and qualities of the surfaces in contact
A child tugs on a rope attached to a 0.2 kg toy with a horizontal force of 16.3 N. A puppy pulls the toy in the opposite direction with a force of 15.8 N. what is the acceleration of the toy?
EF = MA 16.3 -15.8 = 0.5 EF = 0.5 0.5 =0.62(A) A = 0.8 m/s^2 in the direction of the child
In interactions of action reaction pairs involving earth and every day objects, the effect on earths motion is often negligible because..
Earth has great inertia
A plank is inclined at angle theta, north of west. The direction of the normal force exerted by that plank on an object would be oriented at angle theta,...
East of north
While deciding where to drive a supporting nail, you were pressing an 18 N picture frame against the wall to keep it from falling. What is the minimum force perpendicular to the wall that you must exert on the frame to keep it stationary? The coefficient of kinetic friction for the two surfaces in contact is 0.42?
F = 18 divided by 0.42 43 N
All of the following statements about kinetic friction are true except?
For an object on an incline, kinetic friction increases as the angle of the incline above the horizontal increases.
Units that measure weights are units of
Force
Which of the following statements describes free body diagrams? I. Force diagrams show vectors as arrows II. Force exerted on the object are represented III. Forces exerted by the object are represented
I and II
Which of the following statements describes an object in equilibrium? I) The object is at rest II) The object is moving at a constant velocity III) The net external force on the object is zero
I, II, III
Which of the following statements are true about the concept of field forces? I. Field forces can exerted by objects that are in physical contact. II. Field forces can be exerted by objects that are not in contact. III. There are only four fundamental field forces.
I, II, and III
Which of the following statements describe force diagrams? I. Force diagrams show force vectors as arrows II. Forces exerted on the object are represented III. Forces exerted by the object are represented
I, II, and III
Which of the following is true about this equation?
II and III
What is true of inertia?
It is described in newtons first law of motion
two dogs are tugging on a toy. One dog pull with a horizontal force of 15 N due North. The other is pulling due east with a horizontal force of 14 N. What is the direction of the net external horizontal force on the toy?
Northeast
Two books are lying next to each other on a library table. The force due to gravity on the first book is 9 N and on the second is 13 N. The gravitational force on the table itself is 125 N. The floor supports the table with an upward force of 147 N. In a free-body diagram of the table, how many contact forces and how many field forces should be represented?
ONE contact force, THREE FIELD FORCES (3, 1)
Only under what conditions is static friction greater than kinetic friction?
Only at the limit of the motion which is the very instant when the object starts moving. NOT MOVING = STATIC FRICTION MOVING = KINETIC FRICTION
A batter strikes a baseball with a bat. Identify an action reaction pair and describe the force is exerted by each
The batter exerts a force on the bat; the bat exerts a force on the batter
In which situation is the net force acting on a car zero?
The car maintains both its speed and direction.
A truck and a car uniformly accelerate from rest to a velocity of 3.0 m/s in equal time intervals. The truck is ten times as massive as the car. Which of the following statements is correct?
The force on the truck is 10 times the force on the car.
While sitting in a lounge chair with the back inclined at an angle of 10° from the vertical, you tuck a pillow between your head and the chair then you lower the chair back to 40° and doze with the pillow in place. How is the net force on the pillow changed?
The net force is 0/does not change because the pillow stays in place (at rest)
Explain how action reaction pairs keep a book sitting on a table in equilibrium.
When a book is placed on a table, it exerts force downwards on the table. The table then exerts an opposite force on the book, keeping it in equilibrium. All arrows would be the same distance because it has equal forces acting on all sides.
A student holds a 6-N block of wood from a spring balance in an express elevator that maintains constant velocity traveling between floors. A spring scale reading of 5.9 N indicates that the elevator is...
ending an ascending trip (when elevators stop after going up and it feels like your feet want to come off the ground)
An action exerted on an object which may change the object's state of rest or motion defines
force
The change in the horizontal velocity of a 12-kg scooter is +0.5 m/s. What is the net horizontal force acting on it?
greater than 0 N
The gravitational force exerted on an object with most likely be represented by which force vector?
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