to rest at time t=1 at the point x=1. No other information is available about its motion during the intermediate time 0<t<1 If $ denotes the instantaneous acceleration of the particle, then:

a) $ cannot remain positive for all t in the time interval 0<t<1

b) |$| can't exceed 2 at any point in its path

c) |$| must be >= 4 at some point in its path

d) $ must change its sign during the motion but no other assertion can be made about with the info give

the answers are (a) and (c)

pls explain how you worked it out.

thanks

Four persons K, L , M, N are initially at the four corners of a square of side 'd'. Each person now starts moving with a uniform speed 'v' IN SUCH A WAY THAT THAT K always moves directly towds. L, L towards M, M towards N AND N TOWARDS K. aFTER WHAT TIME WILL THEY MEET?