# Thread: science- force mass and acceleration

1. ## science- force mass and acceleration

Hey guys please work this out for me showing me the steps and explaining it to me- science is so not my forte.

g= 9.8m/s/s => this is what it says on top of the sheet. Do I really need it?
Neglect friction. FIND THE FORCE REQUIRED.

1) For a 50kg woman on a 20kg bicycle travelling at 6m/s to come to a halt in 2 seconds.

2) To give a mass of 25 kgs. an acceleartion of 18m/s/s.

3) To accelerate a 1500 kg space probe from 54 000 to 54900 kms/hr in 20 seconds.

4) To increase the velocity of a 1 00 kg car from 10m/s to 20m/s in 5 seconds.

2. Originally Posted by delicate_tears
Hey guys please work this out for me showing me the steps and explaining it to me- science is so not my forte.

g= 9.8m/s/s => this is what it says on top of the sheet. Do I really need it?
Neglect friction. FIND THE FORCE REQUIRED.

1) For a 50kg woman on a 20kg bicycle travelling at 6m/s to come to a halt in 2 seconds.

2) To give a mass of 25 kgs. an acceleartion of 18m/s/s.

3) To accelerate a 1500 kg space probe from 54 000 to 54900 kms/hr in 20 seconds.

4) To increase the velocity of a 1 00 kg car from 10m/s to 20m/s in 5 seconds.
$F=ma$

$F$ is the force required or net force.
$m$ is the total mass.
$a$ is the rate of change in velocity.

1)

$F=ma$
$F=m\left(\frac{v-u}{t}\right)$
$F=(50+70)\left[\frac{(0)-(6)}{(2)}\right]$
$F=(120)(-3)$
$F=-360N$

2)

$F=ma$
$F=(25)(18)$
$F=450N$

3)

$\Delta v$
$=54900-54000$
$=900 kmh^{-1}$
$=\left(\frac{900\times 1000}{1\times 60\times 60}\right)ms^{-1}$
$=250ms^{-1}$

$F=ma$
$F=m\left(\frac{\Delta v}{t}\right)$
$F=(1500)\left(\frac{250}{20}\right)$
$F=18750N$

4)

$F=ma$
$F=m\left(\frac{v-u}{t}\right)$
$F=(100)\left[\frac{(20)-(10)}{5}\right]$
$F=200N$