# on17 - (d) velocity is non-zero and acceleration is zero....

This preview shows pages 1–3. Sign up to view the full content.

Solution for On-Line Homework 17 Motion in a Plane II Solution to On-Line Homework Problem 17.1() Problem: Someone gives a block sitting on an incline a nudge, and it starts sliding down the incline. What type of friction exists between the sliding block and the surface of the incline? Select One of the Following: (a-Answer) kinetic (b) static (c) tangential (d) normal (e) Toby Solution The friction between two objects moving relative to each other while still in contact is kinetic friction. Total Points for Problem: 1 Points Solution to On-Line Homework Problem 17.2() Problem: You throw a ball in a high arc to get it over the defenders, to your waiting team mate. You can neglect air resistance, and the ceiling is really high. At the highest point in the ball’s ±ight: 1

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Select One of the Following: (a) velocity and acceleration are both zero. (b-Answer) velocity and acceleration are both non- zero. (c) velocity is zero but acceleration is non-zero.
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: (d) velocity is non-zero and acceleration is zero. (e) Toby Solution In general, two-dimensional, frictionless projectile motion has both horizontal and vertical components (and if there isnt any cross-wind, we can turn three-dimensional mo-tion into two-dimensional motion by choosing our coor-dinate system appropriately). Gravity acts in the vertical direction only, so the horizontal component of the initial velocity is unaected by gravity ( v x ( t ) = v ,x n = zero ). The vertical motion is uniformly accelerated (the acceler-ation due to gravity is always present), and so is quadratic in time. And so x ( t ) = x + v ,x t and y ( t ) = y + v ,y t 1 2 gt 2 and the vector position function is V r ( t ) = p x ( t ) y ( t ) P 2 The x-y graph of this function (parameterized by t ) is a parabola. Total Points for Problem: 2 Points 3...
View Full Document

## This note was uploaded on 05/04/2008 for the course PHYS 2054 taught by Professor Stewart during the Spring '08 term at Arkansas.

### Page1 / 3

on17 - (d) velocity is non-zero and acceleration is zero....

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online