What mechanical work must you do to lift a uniform log that is 2.5 m long and has a mass of 140 kg from the horizontal to a vertical position?

The elasticity of a good is E=0.2. (a) A 3% price increase will cause the demand to -Select--- v by %. (b) A 3% price decrease will cause the demand to --Select--- v by %.

An aircraft designer is considering the design of an aircraft wing. The wing is to be straight and is to have the same airfoil section all the way along the span; this 2D section has a lift curve slope of 5.9 per radian and a zero-lift angle of attack of -1.2°. It can be assumed that the span efficiency factor will be equal to 0.9. It is proposed that the aircraft will be cruising at Mach 0.57 at an 5° angle of attack.a) Calculate the 3D lift coefficient if: a. The wing area is 170m2 and the wingspan is 40m. b. The wing area is 170m2 and the wingspan is 25m.  b) What is the key disadvantage of a low aspect ratio wing for subsonic aircraft?

Jake bungee jumps from a hot air balloon  55 m above the ground. She knows that 5.0 m of bungee cord will stretch by 1.5 m with her weight. What length of rope should she use to just miss the ground?

Ed, Edd and Eddy love to play on a seesaw. It consists of a 1-kg board with a length of 8 meters. One day, the other end broke down. They had to cut it by a meter and maintain the pin support in its original position. Then, they tried the seesaw altogether. Ed (m = 55kg) sat on one side about 3m from the pin while Edd (m = 40kg) and Eddy (m = 40kg) on the other side. If Edd was about 3m as well from the pin, calculate the following:   The manitude of the reaction force (N) exerted by the pin support on the board. Assume Eddy is in between Ed and Edd. (mass of board = 1kg)

the total kinetic energy for a system of connected rigid bodies is the difference of the kinetic energies of all its moving parts true or false

(a) Calculate the force needed to bring a 850 kg car to rest from a speed of 90.0 km/h in a distance of 105 m (a fairly typical distance for a nonpanic stop).N(b) Suppose instead the car hits a concrete abutment at full speed and is brought to a stop in 2.00 m. Calculate the force exerted on the car and compare it with the force found in part (a), i.e. find the ratio of the force in part(b) to the force in part(a).(force in part (b) / force in part (a))

A basket of negligible mass hangs from the school roof by a spring 5.0m long, It hangs 6.0m above the ground. Three students of equal mass, gently lower themselves into the basket and the spring stretches 1.0m for each one. They climb out and then one climbs a ladder on the roof and steps off, landing in the basket and stretching the spring until it just touches the ground. How high was the ladder above the rooftop?

Mr. Muscedere lifts a loaded barbell up 2.2m. This increases the GPE of the barbell by 490J. What is the mass of the barbell?

Consider an elliptically shaped rail PQ in the vertical plane with OP = 3 m and OQ = 4 m. A block of mass 1 kg is pulled along the rail from P to Q with a force of 18 N, which is always parallel to line PQ (see figure). Assuming no frictional losses, the kinetic energy of the block when it reaches Q is (n × 10) J. The value of n is (take acceleration due to gravity = 10 ms -2):3 -3m- 4m 04 90°