Help With Assignment Questions (Forces)

In summary, four scenarios involving calculations of force, mass, and distance were discussed. From Beavis and Butthead changing their masses in space to a tennis racket hitting a ball, and two boxes being pushed on a frictionless surface to a person falling from a building on a different planet, the equations F = GMm/r^2, F = mv/t, and t = √(2s/g) were used to determine the new force of attraction, average force, and time of descent, respectively.
  • #1
_Pistolkisses
3
0
If anyone can give me any steps to take, or formulas to use when solving these I would REALLY appreaciate it. These ones have really stumped me.:frown:

1. Beavis and Butthead are out in space, or you may say "spaced-out". The force of attraction between them is 30N. Suddenly, Beavis takes a blue MEP (mass enhancing pill) and cuts his mass in half, and Butthead takes a green MEP and his mass triples. While they were doing this the distance between them doubled. What is the new force of attraction between them?

2. A tennis racket, in contact with a 55g ball for 0.0050 s, changes the ball's velocity from 30m/s [E] to 40m/s [W]. What is the average force exerted on the ball?

3. Two boxes of canned goods, 35 kg and 10 kg, are side by side on a frictionless surface. A horizontal force of 90N is applied to the 35kg box to move both both boxes. Determine the magnitude of the action and reaction forces between the two boxes.

4. The planet NUR has a radius of 2.4 x 10^6 m and a mass of 2.0 x 10^26 kg. How long would it take a 55kg NURD to hit the ground if he fell from a 30m high building?

Thanks.
 
Physics news on Phys.org
  • #2
1. The new force of attraction between Beavis and Butthead can be calculated using the equation F = GMm/r^2, where G is the gravitational constant, M and m are the masses of Beavis and Butthead, and r is the distance between them. After the MEPs, M becomes 3M and m becomes M/2, so the new force of attraction is (6GM^2)/(4r^2).2. The average force exerted on the ball can be calculated using the equation F = mv/t, where m is the mass of the ball, v is the change in velocity, and t is the time of contact. The average force is (55g x 10 m/s) / 0.0050 s = 11,000 N.3. The magnitude of the action and reaction forces between the two boxes can be calculated using the equation F = mA, where m is the combined mass of the boxes (45 kg), and A is the acceleration of the system. Since the force applied to the 35kg box is 90N and the acceleration is 2 m/s^2, the magnitude of the action and reaction forces between the two boxes is 180 N.4. The time it would take a 55kg NURD to hit the ground if he fell from a 30m high building can be calculated using the equation t = √(2s/g), where s is the height of the building (30m) and g is the gravitational acceleration of the planet (9.8 m/s^2). The time is approximately 1.7 seconds.
 
  • #3


1. To solve this problem, we can use the formula for Newton's Law of Universal Gravitation: F = (Gm1m2)/r^2, where F is the force of attraction, G is the gravitational constant, m1 and m2 are the masses of the two objects, and r is the distance between them. In this case, we know that the distance between Beavis and Butthead doubled, so r is now 2 times its original value. We also know that Beavis' mass is now half of its original value, and Butthead's mass is triple its original value. Plugging in these values into the formula, we get: F = (6.67x10^-11)(0.5m)(3m)/(2r)^2 = 30N. Solving for r, we get r = 0.5m. Therefore, the new force of attraction between Beavis and Butthead is F = (6.67x10^-11)(0.5m)(3m)/(0.5m)^2 = 120N.

2. To solve this problem, we can use the formula F = mΔv/Δt, where F is the average force exerted, m is the mass of the ball, Δv is the change in velocity, and Δt is the time interval. Plugging in the given values, we get: F = (0.055kg)(40m/s - 30m/s)/(0.0050s) = 110N. Therefore, the average force exerted on the ball is 110N.

3. To solve this problem, we can use Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. Therefore, the magnitude of the action force exerted by the 90N force on the 35kg box is 90N. Since the two boxes are in contact with each other, the reaction force exerted by the 35kg box on the 10kg box is also 90N.

4. To solve this problem, we can use the equations of motion under constant acceleration. First, we need to find the acceleration due to gravity on planet NUR, which can be calculated using the formula g = GM/r^2, where G is the gravitational constant, M is the mass of the planet, and r is its radius. Plugging in the
 

Related to Help With Assignment Questions (Forces)

Question 1: What are the different types of forces?

There are four main types of forces: gravitational, electromagnetic, strong nuclear, and weak nuclear. Gravitational forces are responsible for the attraction between objects with mass. Electromagnetic forces are responsible for the interaction between electrically charged particles. Strong nuclear forces are responsible for binding protons and neutrons in the nucleus of an atom. Weak nuclear forces are responsible for radioactive decay.

Question 2: How do forces affect motion?

Forces can cause an object to change its motion in two ways: by changing its speed or by changing its direction. If a force acts in the same direction as an object's motion, it will speed up the object. If a force acts in the opposite direction of an object's motion, it will slow down the object. Forces can also change the direction of an object's motion, causing it to accelerate or decelerate in a different direction.

Question 3: What is the difference between balanced and unbalanced forces?

When the forces acting on an object are equal in magnitude and opposite in direction, they are considered balanced forces. This means that the object's motion will remain unchanged. On the other hand, when the forces acting on an object are not equal, they are considered unbalanced forces. Unbalanced forces will cause the object to accelerate in the direction of the greater force.

Question 4: How can we calculate the net force acting on an object?

The net force on an object is the sum of all the forces acting on it. To calculate the net force, we need to consider the magnitude and direction of each individual force. If the forces are acting in the same direction, we simply add their magnitudes. If the forces are acting in opposite directions, we subtract the smaller magnitude from the larger one. The resulting net force will have the same direction as the larger force.

Question 5: How do forces relate to Newton's laws of motion?

Newton's laws of motion describe how forces affect the motion of objects. The first law states that an object will remain at rest or in motion in a straight line at a constant speed unless acted upon by an unbalanced force. The second law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The third law states that for every action, there is an equal and opposite reaction.

Similar threads

  • Introductory Physics Homework Help
Replies
13
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
502
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
5
Views
7K
  • Introductory Physics Homework Help
Replies
4
Views
7K
  • Introductory Physics Homework Help
Replies
17
Views
9K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Classical Physics
Replies
7
Views
1K
Back
Top