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A kicking-simulation attachment goes on the front of a wheelchair, allowing athletes with mobility impairments to play soccer. The athletes load up the spring shown through a ratchet
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Vector Mechanics For Engineers
- An automobile driver took a curve too fast. The car spun out of control about its center of gravity (CG) and slid off the road in a northeasterly direction. The friction of the skidding tires provided a 0.25 g linear deceleration. The car rotated at 100 rpm. When the car hit the tree head-on at 30 mph, it took 0.1 sec to come to rest. The force exerted by the 100-lb child on her seatbelt harness as a result of the acceleration just prior to impact is 875 lbf 618 lbf 657 lbf 725 lbfarrow_forward2. A block of mass m=3 kg is sliding along a frictionless inclined surface that makes an angle of o = 30°with respect to the horizontal surface. At the lowest points of the inclined surface, a projectile is fired at a speed of v, = 12 m/s that makes an angle 8, = 45° with respect to the horizontal. Our aim of this problem is to find the time when the projectile will hit the block. e = 450 h = ? Ro= 10 m P= 30° x= ? (a) Find the time when the projectile hits the block. (Given, the initial distance between the block and the projectile along the inclined surface at t=0 is R, = 10 m as shown in the figure) Page 1 of 3 (b) Find the height h, where the projectile will hit the block. (c) Now assume that the projectile hits the block at its maximum range R along the inclined surface and the block is not sliding at all. Then find the maximum range along the inclined surface, Rmax = ?arrow_forward(a) Two blocks are joined by an inextensible cable as shown in Figure. If the system is released from rest, determine the velocity of block A after it has moved 2 m by using the data given. Assume that the coefficient of kinetic friction between block A and the plane is ?k = 0.25 and that the pulley is weightless and frictionless.arrow_forward
- 0 A solid cylinder with a radius of r = 0.34 m and a mass of m = 8 kg is attached to a spring with a spring N constant of k = 25. Assume that the cylinder rolls down the ramp without slipping and that the spring m is initially at its natural length (not stretched or compressed). We ro If the ramp is at an angle of 0 = 63° from horizontal, what is the cylinder's angular velocity when it has traveled a distance of d = 0.25 m? rad ∙d. Sarrow_forwardThe disk D, which has weight W = 15 lb, starts from rest on an incline when the constant moment M is applied to it. The disk is attached at its center to a wall by a spring of constant k = 7 ft/lb. The spring is unstretched when the disk is at its starting position. The disk rolls down the incline without slipping. Take R = 5 ft, 0 = 25° and g = 32.2 ft/s². Use for the moment of inertia of the disk about G, IG: Figure D Part B R M mR² wwww 1 of 1 Part A - Draw a free body diagram of the disk. Indicate which forces and/or couples do work on the disk. Determine the value of the moment M for the disk to stop after rolling down a distance d = 5 ft down the incline. You must use the work-energy theorem to solve this question.arrow_forwardProblem 1 The tension in the string of a simple pendulum shown below (inextensible string and a bob) is 8.5N when 0 = 25° . By making use of the polar coordinates, drawing a FBD and a kinetic diagram, calculate the angular velocity and angular acceleration of the bob at this instant. a = (R – RÒ²)e, + (RÖ + 2RÒ)e, Hint: the string is inextensible, so what does it mean for Ř and R ? 0.5 kg A 2 marrow_forward
- 3. A 2-kg ball S is moved in the vertical plane by a robotic arm. When 0= 30°, the angular velocity of the arm about a horizontal axis through O is 50 deg/s clockwise, and the angular acceleration is 200 deg/s² counterclockwise. In addition, the hydraulic element is being shortened at the constant rate of 500 mm/s. Find the minimum gripping force needed to hold the ball is the coefficient of friction between the sphere and gripping surfaces is 0.5. Compare this force to the force needed to hold the sphere in static equilibrium.arrow_forward* Incorrect Calculate the normal reaction forces at A and B. Answers: NA = Ng= i 83.64 i 67.4 lb lbarrow_forwardPart A The system is released from rest at 0= 0° when a constant couple moment M = 100 N·m is applied. (Figure 1) If mass of the cable and links AB and BC can be neglected, and each pulley can be treated as a disk having a mass of 6 kg, determine the speed of the 20-kg block at the instant link AB has rotated 0-90°. Note that point C moves along the vertical guide. Also, the cable does not slip on the pulleys. Express your answer to three significant figures and include the appropriate units. HÅ 1" UP 3.23 A C EWC ? m S Submit Previous Answers Request Answer X Incorrect: Try Again: 4 attempts remaining 50 mm F 200 mm BO E 100 mm V 0 -50 mm D M 100 Nm Aarrow_forward
- The slender bar of mass mrod = 21 kg is moving to the right on frictionless rollers at A and B with the velocity V, when the roller at B strikes the small obstruction C without rebounding. Compute the minimum value of V, for which the bar will reach the vertical position after the impact. A y L= 3 m V1 В C 40° Select one: O a. V1 = 5.824 m/s O b. V = 1.527 m/s c. V = 0 m/s d. V1 = 7.352 m/sarrow_forwardThe 1600 kg car has a velocity of v the driver sees an obstacle 175 m away, in front of the car. It takes 0.8 s for him to react and lock the brake 100 km/h when causing the car to skid. The coefficient of kinetic friction between the tires and the road is p = 0.25. Find the best correct statement(s) from the following for this situation: ,= 100 km/h Select one or more: Work done by the frictionis equal to 617.4 KW The working forces are ficion and the wejght. The car will stop just in front of the pbstacle without hittungui The car will hit the obstadle. The car skid for the distance of 157.34m,arrow_forwardDYNAMICS OF RIGID BODIES ACTIVITY 4 PROBLEM SETS: 1. A cylinder is pulled up a plane by the tension in a rope that passes over a frictionless pulley and is attached to a 70 kg mass. The 45 kg cylinder has radius of 600 mm. The cylinder moves from rest up a distance of 5 m. What will be its speed? 60° 70 kg 2. The 7 kg block is released from rest and slides a distance s down the inclined plane. It strikes the spring, which it compresses 75 mm before motion impends up the plane. Assuming that the coefficient of friction is 0.25 and that the spring constant k = 2.8 N/mm, determine the value of S. 7 x 9.8 30°arrow_forward
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