Exam 4: Applying Newtons Laws

As shown in the figure,two blocks are connected by a very light string,and the upper block is pulled upward by a different string.The masses of the upper and lower blocks are 300 g and 240 g,respectively.The string between the blocks will break if it exerts a force that exceeds 3.6 N,and the string that pulls the combination upward will break if it exerts a force that exceeds 7.8 N. (a)What is the largest upward acceleration that the blocks can be given without either string breaking? (b)If the upward acceleration is slightly higher than this,which string breaks,the upper one or the lower one?

You push downward on a trunk at an angle 25° below the horizontal with a force of $750 \mathrm {~N}$ If the trunk is on a flat surface and the coefficient of static friction between the surface and the trunk is 0.61,what is the most massive trunk you will be able to move?

Three forces are exerted on an object and as a result the object moves with a constant velocity.One force is 60.0 N along the +x-axis,and the second is 75.0 N along the +y-axis.What is the magnitude of the third force?

A plane flying horizontally at a speed of 50 m/s and at an elevation of 160 m drops a package,and 2.0 s later it drops a second package.How far apart will the two packages land on the ground if effects of air resistance are negligible?

A box of mass 72 kg is at rest on a horizontal frictionless surface.A constant horizontal force of magnitude F then is exerted on the box,accelerating it to the right.You observe that it takes the box 3.4 seconds to travel 13 meters.What is the magnitude of the force F?

A ball rolls over the edge of a platform with only a horizontal velocity.The height of the platform is 1.6 m and the horizontal range of the ball from the base of the platform is 20 m.What is the horizontal velocity of the ball just before it touches the ground? Neglect air.

A boulder rolls off of a very high cliff.If you disregard air,while it is falling,its trajectory is never truly vertical.

An athlete competing in the long jump leaves the ground with a speed of 9.14 m/s at an angle of 55° with the vertical.What is the length of the athlete's jump if air is of no significance?

A girl throws a rock horizontally,with a velocity of 10 m/s,from a bridge.It falls 20 m to the water below.How far does the rock travel horizontally before striking the water,assuming negligible air effects?

A 3.0-kg and a 5.0-kg box rest side-by-side on a perfectly smooth,level floor.A horizontal force of 32 N is exerted on the 3.0-kg box pushing it against the 5.0-kg box,and,as a result,both boxes slide along the floor.How hard do the two boxes push against each other?

A person is pushing on a box exerting a force of magnitude P, as shown in the figure.Earth exerts a force W on the box.The push is directed at an angle θ below the horizontal,and the box remains a rest.The box rests on a horizontal surface that has some friction with the box.The force that the surface exerts on the box perpendicular to the surface is equal to

A hockey puck slides off the edge of a horizontal platform with an initial velocity of 28.0 m/shorizontally in a city where the free-fall acceleration is 9.81 m/s².The height of the platform above the ground is 2.00 m.What is the angle below the horizontal of the velocity of the puck just before it hits the ground if you ignore the effects of air?

A hobbyist launches a projectile from ground level on a horizontal plain.It reaches a maximum height of 72.3 m and lands 111 m from the launch point.Assume no air.What was the angle of launch if g = 9.80 m/s²?

What is the magnitude of the sum of the forces that is required to accelerate a 1200-kg car uniformly from 0 m/s to 27.0 m/s in 10.0 s?

A boy kicks a football from ground level with an initial velocity of 20 m/s at an angle of 30° above the horizontal.What is the horizontal distance to the point where the football hits the ground if we neglect air?

A pilot drops a package from a plane flying horizontally at a constant speed.Neglecting effects of air,when the package hits the ground the horizontal location of the plane will

If a vector pointing upward has a positive magnitude,a vector pointing downward has a negative magnitude.

A flatbed truck is carrying a 20.0-kg crate along a level road.The coefficient of static friction between the crate and the bed is 0.400,and the coefficient of kinetic friction is 0.300.What is the maximum acceleration that the truck can have if the crate is to stay in place relative to the truck?

A projectile is fired from ground level with an initial speed of 55.6 m/s at an angle of 41.2° above the horizontal.Neglect air,take upward as the positive direction,and use g = 9.8 m/s². (a)Determine the time necessary for the projectile to reach its maximum height. (b)Determine the maximum height reached by the projectile. (c)Determine the horizontal and vertical components of the velocity vector at the maximum height. (d)Determine the horizontal and vertical components of the acceleration vector at the maximum height.

As shown in the figure,block B on a horizontal tabletop is attached by very light horizontal strings to two hanging blocks,A and C.The pulleys are ideal,and the coefficient of kinetic friction between block B and the tabletop is 0.100.The masses of the three blocks are m_A = 12.0 kg,m_B = 7.00 kg,and m_C = 10.0 kg.Find the magnitude and direction of the acceleration of block B after the system is gently released and has begun to move.