Exam 4: Applying Newtons Laws

The figure shows a block of mass M hanging at rest.The light wire fastened to the wall is horizontal and exerts a tension force of 38 N on the block.The wire fastened to the ceiling is also very light,exerts a tension force of 59 N on the block, $59 \mathrm {~N} \text {, }$ and makes an angle θ with the ceiling.Find the angle θ.

A ball is thrown horizontally from the top of a tower at the same instant that a stone is dropped vertically.Which object is traveling faster when it hits the level ground below if we neglect air?

A cat leaps to try to catch a bird.If the cat's jump was at 60° off the ground and its initial velocity was $2.74 \mathrm {~m} / \mathrm { s }$ what is the highest point of its trajectory,neglecting effects of air?

A 400-kg box is lifted vertically upward with constant velocity by means of two cables pulling at 40.0° on either side of the vertical direction.What is the tension force that each cable exerts on the box?

A child throws a ball with an initial speed of 8.0 m/s at an angle of 40° above the horizontal.The ball leaves her hand 1.0 m above the ground.Neglect air (a)How far from where the child is standing does the ball hit the ground? (b)How long is the ball in flight before it hits the ground? (c)What is the magnitude of the ball's velocity just before it hits the ground?

James and John dive from an overhang into the lake below.James simply drops straight down from the edge.John takes a running start and jumps with an initial horizontal velocity of 25 m/s.Compare the time it takes each to reach the lake below if we neglect the effects of air.

The coefficients of static and kinetic friction between a 3.0-kg box and a horizontal desktop are 0.40 and 0.30,respectively.What is the force of friction that the desktop exerts on the box when a 15-N horizontal push is exerted on the box?

A 6.00-kg ornament is held at rest by two light wires that form 30° angles with the vertical,as shown in the figure.An external force of magnitude F is exerted vertically downward on the ornament.The two wires exert tension forces denoted by T.A force diagram,showing the four forces that are exerted on the box,is shown in the figure.If the magnitude of force F is 410 N,what is the magnitude of the tension force T?

If a vector $\vec { A }$ has components A_x < 0,and A_y < 0,then the angle that this vector makes with the positive x-axis must be in the range

The horizontal and vertical components of the initial velocity of a football are 16 m/s and 20 m/s respectively.If there is no air,how long does it take the football to reach the top of its trajectory?

Two objects of unequal masses,M and m (M > m),are connected by a very light cord passing over an ideal pulley of negligible mass.When released,the system accelerates,and friction is negligible. Which one of the following force diagrams most realistically represents the forces exerted on the two objects in the moving system?

At target practice,a rifle bullet is fired at an angle of 30° below the horizontal with an initial velocity of 800 m/s from the top of a cliff 80 m high.How far from the base of the cliff does it strike the level ground below if air effects are negligible?

A vector $\vec { A }$ has components A_x = 12.0 m and A_y = 5.00 m. (a)What is the angle that vector $\vec { A }$ makes with the +x-axis? (b)What is the magnitude of vector $\vec { A }$ ?

A 10.0-kg picture is held in place by two wires,the first one hanging at 50.0° to the left of the vertical and the second one at 45.0° to the right of the vertical.What is the tension force that the first wire exerts on the picture?

A projectile is fired at an angle above the horizontal at a location where g = 9.8 m/s².The initial x and y components of its velocity are 86.6 m/s and 50 m/s respectively.At what angle was the projectile fired above the horizontal?

If a vector $\vec { A }$ has components A_x < 0,and A_y > 0,then the angle that this vector makes with the positive x-axis must be in the range

A baseball player is running to second base at 5.03 m/s.When he is 4.80 m from the plate he goes into a slide.The coefficient of kinetic friction between the player and the ground is 0.180,and the coefficient of static friction is 3.14.What is his speed when he reaches the plate?

The x and y components of a vector in a horizontal plane are 4.00 m and 3.00 m,respectively. (a)What is the magnitude of this vector? (b)What angle does this vector make with the positive +y-axis.