Chapter 13, Problem 122P

The 193-kg lunar lander is descending onto the moon's surface with a velocity of 7.5 m/s when its retro-engine is fired. If the engine produces a thrust T for 3.6 s which varies with the time as shown and then cuts off, calculate the velocity of the lander when t = 4.1 s assuming that it has not yet landed. Gravitational acceleration at the moon's surface is 1.62 m/s?. The velocity is positive if moving downward, negative if up. 7.5 m/s T, N 892 1.8 3.6 t, s Answe: v = i m/s

The cars of a roller-coaster ride have a speed of 30km/h as they pass over the top of the circular track neglect any friction and calculate their speed v when they reach the horizontal bottom position. At the top position, the radius of the circular path of their mass centres is 18m, and all six cars have the same mass. Also draw FBD.

The athlete with a mass of 85 kg moves from point A with a velocity vA. The circular orbit it slides has a radius of 4.9 meters and an angle of 60 degrees. As it is know that the reaction force affecting the athlete at the D point is 4. (Coefficient of Dmg); a) Calculate the athlete initial velocity vA and the velocity vB at point B. b) Calculate the height y, which is the highest distance that the athlete can climb after point B, and the distance between BC that he can travel horizontally.

A space shuttle is describing a circular orbit at an altitude of d= 570 km above the surface of the earth. As it passes through Point A, it fires its engine for a short interval of time to reduce its speed by 208 m/s and begin its descent toward the earth. Determine the angle AOB so that the altitude of the shuttle at Point B is 128 km. d B A R = 6370 km The angle AOB is

To place a COmm cations satellite Into a geosynchronous orbit at an alt bove the surface of the ea the satellite is first released from a space shuttle, which is in a circular orbit at an altitude of 185 mi, and is then propelled by an upper-stage booster to its final altitude. As the satellite passes through A, the booster's motor is fired to insert the satellite into an elliptic transfer orbit. The booster is again fired at B to insert the satellite into a geosynchronous orbit. The second firing increases the speed of the satellite by 4870 ft/s. 22 240 mi 185 mi A R= 3960 mi, Determine the speed of the satellite as it approaches Bon the elliptic transfer orbit. (You must provide an answer before moving to the next part.)

A satellite is in a circular earth orbit of radius I'min = 1.67R, where R is the radius of the earth. What is the minimum velocity boost Av necessary to reach point B, which is a distance max = 2.68R from the center of the earth? At what point in the original circular orbit should the velocity increment be added? Answer: Av= i min max B m/s

A roller coaster car has a mass of 600 kg when fully loaded with passengers. If the car has a speed of 20 m/sec at point A, what is the maximum speed the car can have at B and still remain on the track?

Determine the speed of a satellite launched parallel to the surface of the earth so that it travels in a circular orbit 800 km from the earth’s surface.

3. The 60-lb boy swings down as shown in Fig. below. If he starts from rest when 0 = 0°, determine the rate of change in his speed and the tension on each of the two cords of the swing when 0 = 60°. Neglect his size and the mass of seat and cords for the calculation. His speed is actually the speed of boy's center of mass G.