Hi,guys ..........i have a question in my mind always confused me just like newton 3rd law but this one is different. here is my question. I always confuse with the normal force and weight force which is mass * gravity. for example lets say a coin tossed straight upward,and reaches its highest point and falls back down again. 1.here is my question when the coin is moving upward after it released. is it the force down or up?.................because i am confuse with the normal force and the weight force thats pulls the coin down.I know the normal force always be up and weight force be down.but how do we know the force is up and down. and also how do we know if it is decreasing and increasing. 2. my second question how about if the coin at highest point . is the force will be down or up ..but my guess is 0 because the acceleration will be zero. thanks.