Explain Bernoulli's principle with respect to wind and curtains, and calculate the volume of copper with a mass that weighs 30kg on Earth but on the Moon.

Step 1: Answer Question 4. This observation is explained by Bernoulli's principle. When strong wind blows past the partially open window, the air outside moves at a higher speed. According to Bernoulli's principle, faster-moving fluid (air) has lower pressure. Therefore, the pressure outside the window becomes lower than the static air pressure inside the room. The higher pressure inside the room pushes the curtains outwards towards the region of lower pressure. Step 2: Answer Question 5. First, calculate the weight of 30 kg of water on Earth. Given: Mass of water m_water = 30 kg Gravitational field strength on Earth g_earth = 9.8 m s^-2 (standard value) Weight on Earth W_earth = m_water × g_earth W_earth = 30 kg × 9.8 m s^-2 = 294 N Next, determine the mass of copper needed to have this same weight on the Moon. Given: Gravitational field strength on Moon g_moon = 1.625 m s^-2 Weight on Moon W_moon = 294 N Weight on Moon W_moon = m_copper × g_moon 294 N = m_copper × 1.625 m s^-2 m_copper = 294 N1.625 m s^-2 ≈ 180.923 kg Finally, calculate the volume of copper. Given: Density of copper _copper = 896 kg m^-3 Mass of copper m_copper = 180.923 kg Volume of copper V_copper = m_copper_copper V_copper = 180.923 kg896 kg m^-3 ≈ 0.20192 m^3 The volume of copper needed is 0.202 m^3. Step 3: Answer Question 6. First, calculate the net horizontal and vertical forces from Figure 3. Horizontal forces: Force to the right = 14 N Force to the left = 8 N Net horizontal force F_x = 14 N - 8 N = 6 N (to the right) Vertical forces: Force downwards = 32 N Net vertical force F_y = 32 N (downwards) The resultant force is the vector sum of these net forces. Magnitude of resultant force R = sqrt(F_x^2 + F_y^2) R = sqrt((6 N))^2 + (32 N)^2 R = sqrt(36 + 1024) R = sqrt(1060) ≈ 32.56 N The resultant force is a vector of magnitude 32.56 N pointing to the right and downwards. To draw the resultant force in Figure 4, draw an arrow originating from the center of the body, pointing towards the bottom-right corner. The length of the arrow should be proportional to 32.56 N. The angle it makes with the horizontal (pointing right) is given by = (32)/(6), so ≈ 79.4^ below the horizontal. [Drawing description for Figure 4]: Draw a single arrow originating from the center of the square in Figure 4. This arrow should point downwards and to the right. The horizontal component of this arrow should represent 6 N to the right, and the vertical component should represent 32 N downwards. Step 4: Answer Question 7. Door handles are placed as far away from the hinges as possible to maximize the moment arm. The moment (or torque) required to open or close a door is the product of the applied force and the perpendicular distance from the pivot (hinges) to the line of action of the force. By increasing this distance, a smaller force is needed to produce the same turning effect, making it easier to open or close the door. Step 5: Answer Question 8. It is easier to drive a nail into a piece of wood using a steel hammer than a wood mallet because a steel hammer has a greater mass and is harder than a wood mallet. When striking the nail, the steel hammer delivers a larger impulse and exerts a greater force over a very short contact time. This larger force, concentrated on the small area of the nail head, results in a higher pressure, which is more effective at overcoming the resistance of the wood and driving the nail in. Last free one today — make it count tomorrow, or type /upgrade for unlimited.