A net force of 20 N acts on a 5 kg mass kept at
rest. Distance travelled by the mass in 6 s is
(1) 72 m
(2) 36 m
(3) 24 m
(4) 12 m
000 kand 2ko are fixed at a
Answers
Answer :
Distance travelled by the mass in 6 s is :-
Option (1) 72 m
Given :
• Force applied on the mass = 20 N
• Mass = 5 kg
• The mass is initially at rest.
• Time taken by the mass to travel a particular distance = 6 s
• Initial velocity = 0 m/s²
To find :
• Distance travelled by the mass = ?
Concept :
Here, we have to find the distance travelled by the mass. So in order to find the distance firstly, we will calculate the acceleration of the mass by using the formula of force. As we don't have the value of 'v' final velocity so we will use the second equation of motion to find the distance travelled by the mass.
Formula of force :-
- Force = m × a
where,
• m denotes the mass of the body
• a denotes the acceleration
Second equation of motion :-
- s = ut + ½ at²
where,
• s denotes the distance/displacement
• u denotes the initial velocity
• a denotes the acceleration
• t denotes the time taken
Solution :
Calculating the acceleration of the mass :-
→ Force = ma
→ Substituting the given values :
→ 20 = 5 × a
→ Transposing 5 to the left hand side :
→ 20 ÷ 5 = a
→ 4 = a
→ The value of a = 4
• Acceleration of the mass = 4 m/s²
Now, calculating the distance travelled by the mass :-
→ Second equation of motion :
→ s = ut + ½ at²
→ Substituting the given values :
→ The value of 'u' is zero because the body is initially at rest.
→ s = (0)(6) + ½ (4)(6)²
→ s = 0 + ½ × 4 × 6 × 6
→ s = 2 × 6 × 6
→ s = 72
→ The value of s = 72
Therefore, the distance travelled by the mass = 72 m