an object moving with a velocity of 20m/s increases to velocity of 40m

1.	an object moving with a velocity of 20m/s increases to velocity of 40m/s in 5sec if the mass of an object is 5kg find out external force acting on it
Answer» Answer: the required answer is 20 Newton GIVEN: initial velocity, u=20m/s final velocity , V=40m/s time,t = 5 s mass ,m = 5 kg TO FIND: external force, f KEYS: f.......force m..... mass a...... ACCELERATION u..... initial velocity v.......final velocity t......time s..... displacement FORMULAE TO BE USED: according to Newton's second law of motion f= ma according to first EQUATION of motion v = u + at SOLUTION: STEP 1: TO FIND ACCELERATION USING FIRST EQUATION OF MOTION $v = u + at \\ \\ 40 = 20 + a(5) \\ \\ 40 - 20 = 5a \\ \\ 20 = 5a \\ \\ a = 20 \div 5 \\ \\ a = 4m/s^2$ Acceleration, a= 4 m/s^2 STEP2: TO FIND FORCE $f = ma \\ \\ f = 5 \times 4 \\ \\ f = 20 \: newton$ force is 20 N RELATED FORMULAE: FIRST EQUATION OF MOTION $v = u + at$ SECOND EQUATION OF MOTION $s = ut + \frac{1}{2} a {t}^{2}$ THIRD EQUATION OF MOTION ${v}^{2} - {u}^{2} = 2as$

an object moving with a velocity of 20m/s increases to velocity of 40m/s in 5sec if the mass of an object is 5kg find out external force acting on it

Answer»

Answer:

the required answer is 20 Newton

GIVEN:

initial velocity, u=20m/s
final velocity , V=40m/s
time,t = 5 s
mass ,m = 5 kg

TO FIND:

external force, f

KEYS:

f.......force
m..... mass
a...... ACCELERATION
u..... initial velocity
v.......final velocity
t......time
s..... displacement

FORMULAE TO BE USED:

according to Newton's second law of motion

f= ma

according to first EQUATION of motion

v = u + at

SOLUTION:

STEP 1: TO FIND ACCELERATION USING FIRST EQUATION OF MOTION

$v = u + at \\ \\ 40 = 20 + a(5) \\ \\ 40 - 20 = 5a \\ \\ 20 = 5a \\ \\ a = 20 \div 5 \\ \\ a = 4m/s^2$

Acceleration, a= 4 m/s^2

STEP2: TO FIND FORCE

$f = ma \\ \\ f = 5 \times 4 \\ \\ f = 20 \: newton$

force is 20 N

RELATED FORMULAE:

FIRST EQUATION OF MOTION

$v = u + at$

SECOND EQUATION OF MOTION

$s = ut + \frac{1}{2} a {t}^{2}$

THIRD EQUATION OF MOTION

${v}^{2} - {u}^{2} = 2as$