If multiple forces are acting on an object, which statement is always true? (1 point)
A.) The acceleration will be directed in the direction of the net force.
B.) The acceleration will be directed in the direction of the gravitational force.
C.) The acceleration will be directed in the direction of the applied force.
D.) The acceleration will be directed in the direction of the normal force.
A) The acceleration will be directed in the direction of the net force.
If a ball is accelerating down through the air with no horizontal motion, what must be true about the net forces acting on the ball? (1 point)
A.) The gravitational force is greater than the drag.
B.) The net force on the ball is zero.
C.) The drag is greater than the gravitational force.
D.) The net force on the ball is directed upward.
A) The gravitational force is greater than the drag.
A boy who exerts a 300-N force on the ice of a skating rink is pulled by his friend with a force of 75 N, causing the boy to accelerate across the ice. If drag and the friction from the ice apply a force of 5 N on the boy, what is the magnitude of the net force acting on him? (1 point)
A.) 380 N
B.) 70 N
C.) 370 N
D.) 80 N
The net force acting on the boy can be calculated by subtracting the forces that oppose his motion from the applied forces:
Net force = Applied force - Opposing forces
The applied force is the sum of the force exerted by the boy and his friend:
Applied force = 300 N + 75 N = 375 N
The opposing forces are the drag force and the force of friction:
Opposing forces = Drag force + Friction force = 5 N
Net force = 375 N - 5 N = 370 N
Therefore, the magnitude of the net force acting on the boy is 370 N.
The correct answer is C) 370 N.
Four friends push on the same block in different directions. Allie pushes on the block to the north with a force of 18 N. Bill pushes on the block to the east with a force of 14 N. Chris pushes on the block to south with a force of 23 N. Debra pushes on the block to the west with a force of 20 N. Assuming it does not move vertically, in which directions will the block move? (1 point)
A.) north and east
B.) north and west
C.) south and east
D.) south and west
To determine the directions in which the block will move, we need to find the net force acting on the block.
First, let's add up the forces in the north-south direction: Allie is pushing north with 18 N, and Chris is pushing south with 23 N. The net force in the north-south direction is:
Net force north-south = 18 N - 23 N = -5 N
Next, let's add up the forces in the east-west direction: Bill is pushing east with 14 N, and Debra is pushing west with 20 N. The net force in the east-west direction is:
Net force east-west = 14 N - 20 N = -6 N
Since the net force in both the north-south and east-west directions is negative, it means that the block will move in the opposite directions of the forces applied. Therefore, the block will move to the north and to the west.
Therefore, the block will move in the direction given as option B) north and west.
Two teams are playing tug of war. The tables show the members of each team and how much pulling force each team member applies to the rope.
Team A
Members Pulling Force (N)
Darlene 360
Eric 400
Keshawn 450
Team B
Members Pulling Force (N)
Anita 350
Frank 390
Molly 490
If Team A pulls to the right and Team B pulls to the left, what is the total horizontal net force applied to the rope? (1 point)
A.) 20 N to the left
B.) 20 N to the right
C.) 40 N to the right
D.) 40 N to the left
To determine the total horizontal net force applied to the rope, we need to calculate the sum of the forces exerted by each team:
Team A:
Darlene: 360 N (to the right)
Eric: 400 N (to the right)
Keshawn: 450 N (to the right)
Team B:
Anita: 350 N (to the left)
Frank: 390 N (to the left)
Molly: 490 N (to the left)
To find the net force, we can sum up the forces for both teams, taking into account their direction:
Net force = (Darlene + Eric + Keshawn) - (Anita + Frank + Molly)
= (360 N + 400 N + 450 N) - (350 N + 390 N + 490 N)
= 1210 N - 1230 N
= -20 N
The net force is -20 N, which means it is 20 N to the left.
Therefore, the correct answer is D) 40 N to the left.