1. What is the weight of a 2.88 kg snake?
2. A girl drops a rock straight down from a bridge. Assume negligible air resistance. How fast is it going 4.0 s later?
3. A rock with a mass of 22.45 kg is falling from a tall tower.
a. What is the Net Force if the rock is in free fall?
b. What is the Net Force if the rock experiences an air resistance of 16.44 N
c. What is the Net Force when the rock reaches its terminal velocity of – 15m/s?
4. A 75.0 kg person stands on a scale in an elevator.
a. . What does the apparent weight (scale read) when the elevator is at rest?
b. . What does the apparent weight (scale read) when the elevator is climbing at a constant speed of + 3.00 m/s?
c. . What does the apparent weight (scale read) when the elevator accelerates upwards at + 1.46 m/s2?
d. . What does the apparent weight (scale read) when the elevator accelerates downwards at - 1.46 m/s2?
5. Before a sky diver opens his parachute, he may be falling at a velocity higher than the terminal velocity he will have after the parachute opens.
a) Describe what happens to his velocity as he opens the parachute.
b) Describe his velocity from after his parachute has been open for a time until he is about
to land.
6. From the top of a tall building, you drop two tennis balls, one ball is filled with air and the
other ball is filled with lead. Both experience air resistance as they fall.
a. Which ball reaches terminal velocity first?
b. Do both balls hit the ground at the same time? Explain.
7. A book weighing - 14.55 N rests on an inclined plane at 36o from the horizontal.
a. Make a drawing of this situation. Draw and label the various force vectors
b. Find the components of the weight parallel and perpendicular to the plane.
8. A fisher in a boat is using a “10-lb test” fishing line. This means that the line can exert a force of 44 N without breaking (1 lb = 4.4 N). (Hint: make a drawing of the forces acting on the fish.)
a) How heavy a fish can the fisher catch if he pulls the fish up vertically at constant speed? (2 marks)
b) How heavy a fish can this person catch if the fish occasionally accelerates at 3.0 m/s2 downward?
1. Wt. = m*g = 2.88 * 9.8 = 28.2 Newtons
2. V=Vo * gt. Vo = 0,g = 9.8m/s^2,t=4s.
3. Fn = m*g.
3b. Fn = m*g - 16.44
1. To find the weight of an object, you need to multiply its mass by the acceleration due to gravity. In this case, the mass of the snake is given as 2.88 kg. The acceleration due to gravity on Earth is approximately 9.8 m/s^2. So, the weight of the snake would be:
Weight = Mass * Acceleration due to gravity
Weight = 2.88 kg * 9.8 m/s^2
2. To determine the speed of the rock, you can use the equation for uniform acceleration:
Final velocity = Initial velocity + (Acceleration * Time)
Initial velocity = 0 m/s (as it is dropped from rest)
Acceleration = 9.8 m/s^2 (acceleration due to gravity)
Time = 4.0 s
Final velocity = 0 m/s + (9.8 m/s^2 * 4.0 s)
3. a) When the rock is in free fall, it is not experiencing any opposing forces, so the net force is simply the force due to gravity acting on it. The force due to gravity is given by:
Force due to gravity = Mass * Acceleration due to gravity
b) When the rock experiences air resistance, the net force is the force due to gravity minus the force of air resistance. So, the net force would be:
Net force = Force due to gravity - Force of air resistance
c) When the rock reaches its terminal velocity, the net force becomes zero, as the force due to gravity is balanced out by the force of air resistance. So, the net force is zero when the rock reaches its terminal velocity.
4. a) When the elevator is at rest, the apparent weight (scale reading) would be equal to the person's actual weight, as there is no acceleration or opposing force acting on the person.
b) When the elevator is climbing at a constant speed, there is no net force on the person, so the apparent weight would again be equal to the person's actual weight.
c) When the elevator accelerates upwards, the net force on the person is the sum of the force due to gravity and the force due to the upward acceleration of the elevator. The apparent weight would be the magnitude of this net force.
d) When the elevator accelerates downwards, the net force on the person is the force due to gravity minus the force due to the downward acceleration of the elevator. The apparent weight would be the magnitude of this net force.
5. a) When the skydiver opens his parachute, it increases the surface area and thus the air resistance acting on the skydiver. This increase in air resistance slows down the skydiver's descent and reduces his velocity.
b) After the parachute has been open for a while, the skydiver reaches his terminal velocity. At this point, the forces of gravity and air resistance are balanced, resulting in a constant velocity until he is about to land.
6. a) The ball filled with lead will reach terminal velocity first. This is because the ball filled with lead has a higher mass, which means it experiences a greater force of gravity and, therefore, a higher terminal velocity.
b) Both balls will hit the ground at the same time. Terminal velocity occurs when the force of gravity is balanced by the force of air resistance. Once this balance is achieved, the velocity of the objects remains constant, regardless of their masses. Therefore, both balls will fall at the same rate and hit the ground at the same time.
7. a) You can draw a diagram with an inclined plane at an angle of 36 degrees from the horizontal. Label the weight vector pointing straight downwards and the components of the weight vector parallel and perpendicular to the plane.
b) To find the components of the weight vector parallel and perpendicular to the plane, you can use trigonometry. The component of the weight parallel to the plane can be found by multiplying the weight by the sine of the angle between the weight vector and the plane. The component of the weight perpendicular to the plane can be found by multiplying the weight by the cosine of the same angle.
8. a) To determine how heavy a fish the fisher can catch if they pull the fish up vertically at a constant speed, you can equate the force exerted by the fishing line to the weight of the fish. The force exerted by the fishing line is given as 44 N (10-lb test line).
Weight of the fish = Force exerted by the fishing line
Weight of the fish = 44 N
b) If the fish occasionally accelerates downward at 3.0 m/s^2, the force exerted by the fishing line would need to be greater than the weight of the fish plus the force required to accelerate the fish downward. The force exerted by the fishing line can be calculated using the equation:
Force exerted by the fishing line = Weight of the fish + Mass of the fish * Acceleration due to gravity
You would need to solve for the maximum mass of the fish that can be caught, given the force exerted by the fishing line.