# Homework Help: Help force vector problem

1. Nov 26, 2012

### physicshawk

help !!!force vector problem

A cricket ball has weight 1.6 N. At any instant between being struck by the bat and reaching...?
the ground the ball is subject to a resistive force of constant magnitude 0.5 N. (I have solved the following part with inverted commas but I am mentioning it case it be of use to answer the next part of the question which I need to know about.)

“The diagram shows the directions in which the resistive force acts
i) immediately after the ball leaves the bat,

ii) at the highest point of the flight,

iii) immediately before the ball reaches the ground.

The resultant of the resistive force and the weight if the cricket ball is denoted by R. Find the magnitude and direction of R in each of the three cases.”

for the diagram see: http://www.flickr.com/photos/8625954...in/photostream [Broken]

Assuming that the resistive force acts in a direction opposite to that in which the cricket ball is moving, state at which stage of the flight

a) the magnitude of the resultant is greatest

b) the angle between the resultant and the vertical is greatest.

I am able to vaguly work out part a but I don't know the approach to part b.

Last edited by a moderator: May 6, 2017
2. Nov 26, 2012

### Bill Nye Tho

Re: help !!!force vector problem

3. Nov 26, 2012

### Basic_Physics

Re: help !!!force vector problem

R is the resultant of the weight of the ball and the resistive force. So you have a parallelogram with R being the diagonal. The vertical weight leg is downwards and a constant length. The other leg's direction and magnitude changes during the course of the parabolic trajectory.

Last edited: Nov 26, 2012
4. Nov 26, 2012

### physicshawk

Re: help !!!force vector problem

sorry. will look into it and fix it as soon as possible.