Abox is held at rest by two ropes that form 30° angles with the vertical. the tension t in either rope is 42 n. what is the weight (w) of the box?

1134567 a jet with mass m = 1.1 ă— 105 kg jet accelerates down the runway for takeoff at 2 m/s2. 1) what is the net horizontal force on the airplane as it accelerates for takeoff? 2.2*10^5 n your submissions: 2.2*10^5 computed value: 220000submitted: saturday, january 26 at 2: 41 pm feedback: correct! 2) what is the net vertical force on the airplane as it accelerates for takeoff? 0 n your submissions: 0 computed value: 0submitted: saturday, january 26 at 2: 41 pm feedback: correct! 3) once off the ground, the plane climbs upward for 20 seconds. during this time, the vertical speed increases from zero to 21 m/s, while the horizontal speed increases from 80 m/s to 95 m/s. what is the net horizontal force on the airplane as it climbs upward? n 4) what is the net vertical force on the airplane as it climbs upward? n 5) after reaching cruising altitude, the plane levels off, keeping the horizontal speed constant, but smoothly reducing the vertical speed to zero, in 13 seconds. what is the net horizontal force on the airplane as it levels off? n 6) what is the net vertical force on the airplane as it levels off?

Aheat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. the same engine running backward is called a heat pump if its purpose is to exhaust warm air into the hot reservoir. heat pumps are widely used for home heating. you can think of a heat pump as a refrigerator that is cooling the already cold outdoors and, with its exhaust heat qh, warming the indoors. perhaps this seems a little silly, but consider the following. electricity can be directly used to heat a home by passing an electric current through a heating coil. this is a direct, 100% conversion of work to heat. that is, 19.0 \rm kw of electric power (generated by doing work at the rate 19.0 kj/s at the power plant) produces heat energy inside the home at a rate of 19.0 kj/s. suppose that the neighbor's home has a heat pump with a coefficient of performance of 4.00, a realistic value. note: with a refrigerator, "what you get" is heat removed. but with a heat pump, "what you get" is heat delivered. so the coefficient of performance of a heat pump is k=qh/win. an average price for electricity is about 40 mj per dollar. a furnace or heat pump will run typically 200 hours per month during the winter. what does one month's heating cost in the home with a 16.0 kw electric heater? what does one month's heating cost in the home of a neighbor who uses a heat pump to provide the same amount of heating?

Cathy is pedaling down a steep hill on her bicycle and wants to be able to coast up the next hill, which is 25 meters high, without pedaling. cathy and her bicycle have a mass of 75 kg. assuming her bicycle is 100% efficient, what would her speed have to be?