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A Ball is Thrown

(1) A ball is thrown horizontally from a height of 20.8m and hits the ground with a speed that is three times its initial speed. What was the initial speed? (2) A ball is shot from the ground into the air. At a height of 9.1m, the velocity is observed to be V = 7.9i + 5.1j in m/s (i horizontally, j upward). To what maximum he

Projectiles and Vectors

1. a) A projectile is fired horizontally from a gun that is 37.0 m above the flat ground. The muzzle velocity is 275 m/s. How long does the projectile remain in the air? b) At what horizontal distance from the firing point does it strike the ground? c) What is the speed as it strikes the ground? 2. a) A watermelon has t

Issues of Friction

I'm completely lost - Could you go step by step so I can follow your logic? Thanks. 1. A crate sits on a flatbed truck. This truck, initially travelling at a velocity of 80 km/hour, comes to a stop in 22 meters. What is the minimum coefficient of static friction required between the crate and truck bed, if it is not to sli

Speed and Velocity Problem Set

1) A blink lasts 100 milliseconds. How far does one travel in meters, if the planes average velocity is 2040mph? 2) A particles position is x=5-12t+3t^2, v=6t-12. The velocity at 1 sec = 6m/s. Is it moving toward x just then? 3) What is its speed just then? 4) Is the speed larger or smaller at much later times? 5) At what

Speed and Velocity

1) Jack travels from A to B at 30mph and returns at 10mph. Jill leaves at the same time as Jack, and travels from A to B and back at a constant speed of 20mph. Who gets back first? 2) Assume that East Lak Road runs due east from the Walmart and there are markers along it, ten miles from walmart, etc. a car starts at the 12


A sign is hung from a pole with two equal cable segments making an angle of 82 degrees. What is the resultant force of both cable segments have a force of 65 lbs? A duck flies south at a velocity of 18 ft/s. If a cross wind blows west at a velocity of 5 ft/s, what is the velocity and direction the duck is flying?

Velocity within Skiing

Ben is skiing downhill at a constant 8.0 m/s when he reaches an icy patch on which his skis move with negligible friction. If the icy patch is 37 m long and drops 15 m in elevation, what is Ben's speed at the end of the icy patch?

Horizontal and Vertical Velocity

A pellet launch is found to propel a metal ball sideways a distance of 2m, when the angle of launch is 36.9 degrees. a) What do you have to do to the initial velocity- in terms of x and y components? b) What variable is common to both horizontal and verticle motion? Find the variable. c) Use the b) value to answer this: If

Head-On Collisions

In a head-on collision where the carts stick together after the collision, a) What combinations of velocities will cause two carts of the same mass to be at rest after the collision? Explain. b) What happens if a less massive cart is moving much faster than a more massive cart? Much slower? Explain. c) What mathematical defin

String Attached to a Block on a Horizontal Surface

Consider a string attached to a block on a horizontal surface. If you gradually pull very gently and horizontally on the string and increase the force very slowly until the block moves at a constant velocity. What happens to the frictional force just as the block begins to slide? Explain.

Average Landing Force Needed

A person about to jump from a 1.6m high platform wants to limit the average stopping force on landing to 12 times her weight. By how much will it be necessary to lower herself by flexing her knees? Give an algebraic rather than numerical answer. Compare that work with the original potential energy she had before she jumped.

Physics Wave Problems

11. A particle in simply harmonic motion has a frequency of 40 Hz. What is the period of this oscillation? 17. (a) At what position is the speed of mass in a mass-spring system maximum? (1) x = 0, (2) x = -A, or (3) x = +A. Why? (b) If m = 0.250 kg, k = 100 N/m, and A = 0.10 m, what is the maximum speed? 33. The simple pe

Calculating Recoil Velocity

Starting from rest, two skaters "push off" against each other on smooth level ice, where friction is negligible. The little one has a mass of 54-kg and the bigger one has a mass of 88-kg. Assuming the little one coasts away with a velocity of 2.5 m/s due north, determine the recoil velocity of the bigger skater.

Average Force Exerted

A 140 gram baseball has a velocity of 38 m/s as it approaches a bat. The bat applies a force and the ball departs in the opposite direction at 58 m/s. The contact time between the bat and the ball is 4.0 ms. Determine the average force exerted on the ball by the bat.

"Ball Kick"

A man kicks a 200g ball such that it leaves the ground at an angle of 30 degrees with the horizontal and strikes the ground at the same elevation a distance of 15m away. Determine the impulse of his foot on the ball. Neglect the impulse caused by the ball's weight while its being kicked.

Block Up Ramp

A 5-lb block is given an initial velocity of 10 ft/s up a 45 degree smooth slope. Determine the time it will take to travel up the slope before it stops.

Force, Velocity, Potential Energy (Energy Law)

A girl has a mass of 40kg and center of mass at G. If she is swinging to a maximum height defined by theta = 60 deg, determine the force developed along each of the four supporting posts such as AB at the instant theta = 0 deg. The swing is centrally located between the posts. *See attachment for diagram

Conservation of momentum

Jonathan and Jane are sitting in a sleigh that is at rest on frictionless ice. Jonathan's weight is 800 N, Jane's weight is 600 N, and that of the sleigh is 1000 N. They see a poisonous spider on the floor of the sleigh and immediately jump off. Jonathan jumps to the left with a velocity (relative to the ice) of 5.00 m/s at 30 d

Analyzing Elastic Collision in One Dimension

Blocks of mass m and 2m are positioned on a semicircular frictionless track at a height of R/4 above the lowest point. The blocks are released simultaneously and collide elastically. How high does each block rise after the collision?

Rocket Ejection and Linear Momentum

A rocket with initial mass of 8.0 x 10^3 kg is fired vertically. Its exhaust gases have a relative velocity of 2.5 x 10^3 m/s and are ejected at a rate of 40 kg/s. a) What is the initial accerleration of the rocket? b) What is the acceleration after 20s have elapsed?

Angular momentum

A hockey stick of mass m_s and length L is at rest on the ice (which is assumed to be frictionless). A puck with mass m_p hits the stick a distance D from the middle of the stick. Before the collision, the puck was moving with speed v° in a direction perpendicular to the stick. The collision is completely inelastic, and the pu

Deer Hunting Kinematics

A man is deer hunting by a cliff that is 1000.0 m tall. He fell asleep while hunting and woke up at night. He decided to shoot off a few rounds to try and get the attention of someone. If he aims 65 degrees above the horizontal and fires a bullet that leaves his gun at 410.00 m/s over the cliff how long will the bullet rise?

Two problems in basic Physics: Force and Direction

Problem 1: A box of mass M is held against the ceiling by a force P acting at an angle (SYMBOL1) as shown. The block slides along the ceiling to the right at a constant speed. The coefficient of kinetic friction between the box and the ceiling is (SYMBOL2). (a) Draw a labled free body diagram for the box (b) Determine the f

Toy Car: Actual translational speed of the car; angular velocity of the flywheel

When a toy car is rapidly scooted across the floor, it stores energy in a flywheel. The car has mass 0.180g, and its flywheel has a moment of inertia of 4.00*10^(-5)kg.m^2. The car is 15.0cm long. An advertissement claims that the car can travel at a scale speed of up to 700km/h (440mi/h). The scale speed is the speed of the toy

Mechanics: velocity and kinetic energy

A Steel pile is driven a distance (d) into the ground by a hammer of mass (M) 450kg, dropped from a height (h) of 3.25m above the top of the pile. The mass of the pile (m) is 40kg and the average resistance of the ground to penetration (Fr) is 45kN. Calculate: a. The velocity and the kinetic energy of the hammer immediatel

Momentum of a Broken Spaceship Piece After Explosion

A spaceship of mass 2.3*10^6 kg is cruising at a speed of 4.4*10^6 m/s when the antimatter reactor fails, blowing the ship into three pieces. One section, having a mass of 5.1*10^5 kg, is blown straight backward with a speed of 2.1*10^6 m/s. A second piece, with mass 7.6*10^5 kg, continues forward at 1.1*10^6 m/s. What is the sp