Practice+questions

Hey, just thought i'd post the questions we practiced in class on here, so we can remeber how to do them...


 * __NOTE:__** Remember to always state what equation you're using e.g. calculate the speed: speed equals distance divided by time.[[image:triangle.jpg align="right"]]


 * __Motion__**

A) Calculate the speed of a runner who travels 400m in 67s. //speed equals ditance divided by time.// S= 400m/67s = 5.97 m/s (2 d.p)

B) A motorbike travels for 50 seconds at a speed of 28m/s. how far does it travel? //distance equals speed times time. d= 28m/s x 50s = 1400m//

C) A plane flies for 4 hours at a ground speed of 550km/h. how far does it go? //first of all you need to convert hours to seconds and kilometres to metres. 4 hrs = 14400 seconds. 550km/h =550000m/3600s=152.78m/s distance equals speed times time. d= 152.78m/s x 14400s = 2,200,000m// Or you could do 4*550=2200km then 2200*1000(to convert to metres)=2,200,000m

D) A car goes on a journey of 200km at an average speed of 80km/h. how long will the journey take? //200km/ 80km/h time equals distance divided by speed. t= 200/80 = 2.5 hours (as we need to give answers in SI units, we then convert this into seconds.// 2.5 hours X 60 = 150 mins (this is still not in SI units, therefor)... 150 mins X 60 = 9000seconds


 * __Forces__**

Mr Clay weighs 800 Newtons on earth. his mass is 80kg on earth. On the moon his weight is 1/6 of that on earth. how much will he weigh on the moon? //Weight: 800 multiplied by 1/6 = 133.33 Newtons on the moon ............... but Mass: 80kg - stays the same.//