Exam 12: Torque

A metal bar is hanging from a hook in the ceiling when it is suddenly struck by a ball that is moving horizontally (see figure).The ball is covered with glue,so it sticks to the bar.During this collision

If = -4 - 2 - 3 ,what is × ?

If the torque on an object adds up to zero

A very thin horizontal,2.00-m long,5.00-kg uniform beam that lies along the east-west direction is acted on by two forces. At the east end of the beam,a 200-N force pushes downward. At the west end of the beam,a 200-N force pushes upward. What is the angular acceleration of the beam?

A 72.0-kg person pushes on a small doorknob with a force of 5.00 N perpendicular to the surface of the door. The doorknob is located 0.800 m from axis of the frictionless hinges of the door. The door begins to rotate with an angular acceleration of 2.00 rad/s². What is the moment of inertia of the door about the hinges?

A dump truck has a large cubical concrete block in its bed.The coefficients of friction between this block and the floor of the bed are µ_k = 0.450 and µ_s = 0.650.As the bed is slowly tilted above the horizontal,will the brick first begin to slide or will it first tip over?

A light board,10 m long,is supported by two sawhorses,one at one edge of the board and a second at the midpoint.A small 40-N weight is placed between the two sawhorses,3.0 m from the edge and 2.0 m from the center.What forces are exerted by the sawhorses on the board?

A 500-g particle is located at the point = 4m + 3m - 2m And is moving with a velocity = 5 m/s -2 ms + 4 m/s )What is the angular momentum of this particle about the origin?

A uniform solid disk of radius 1.60 m and mass 2.30 kg rolls without slipping to the bottom of an inclined plane.If the angular velocity of the disk is 5.35 rad/s at the bottom,what is the height of the inclined plane?

What is the torque about the origin on a particle located at = 3 m + 4 m - 2 m If a force = 5 N - 2 N + 3 N Acts on the particle?

A child is trying to stack two uniform wooden blocks,12 cm in length,so they will protrude as much as possible over the edge of a table,without tipping over,as shown in the figure.What is the maximum possible overhang distance d?

What is the vector product of = 2.00 + 3)00 + 1)00 And = 1)00 - 3)00 - 2)00 ?

A light triangular plate OAB is in a horizontal plane.Three forces,F₁ = 6.0 N,F₂ = 9.0 N,and F₃ = 7.0 N,act on the plate,which is pivoted about a vertical axes through point O.In the figure, ₂ is perpendicular to OB.Consider the counterclockwise sense as positive.The sum of the torques about the vertical axis through point O,acting on the plate due to forces F₁,F₂,and F₃,is closest to

A 95 N force exerted at the end of a 0.50 m long torque wrench gives rise to a torque of 15 N • m. What is the angle (assumed to be less than 90°)between the wrench handle and the direction of the applied force?

A string is wrapped around a pulley with a radius of 2.0 cm and no appreciable friction in its axle.The pulley is initially not turning.A constant force of 50 N is applied to the string,which does not slip,causing the pulley to rotate and the string to unwind.If the string unwinds 1.2 m in 4.9 s,what is the moment of inertia of the pulley?

A 30.0-kg child sits on one end of a long uniform beam having a mass of 20.0 kg,and a 40.0-kg child sits on the other end. The beam balances when a fulcrum is placed below the beam a distance 1.10 m from the 30.0-kg child. How long is the beam?

In the figure,a 10.0-m long bar is attached by a frictionless hinge to a wall and held horizontal by a rope that makes an angle θ of 53° with the bar.The bar is uniform and weighs 39.9 N.How far from the hinge should a 10.0-kg mass be suspended for the tension T in the rope to be 125 N?

The two rotating systems shown in the figure differ only in that the two identical movable masses are positioned at different distances from the axis of rotation.If you release the hanging blocks simultaneously from rest,and if the ropes do not slip,which block lands first?

A uniform solid 5.25-kg cylinder is released from rest and rolls without slipping down an inclined plane inclined at 18° to the horizontal.How fast is it moving after it has rolled 2.2 m down the plane?

What is the magnitude of the cross product of a vector of magnitude 2.00 m pointing east and a vector of magnitude 4.00 m pointing 30.0° west of north?