Answer:
30 minutes
Explanation:
Energy per time is constant, so:
E₁ / t₁ = E₂ / t₂
m₁C₁ΔT₁ / t₁ = m₂C₂ΔT₂ / t₂
(1 kg) C (70°C − 25°C) / 15 min = (1.5 kg) C (80°C − 20°C) / t
(1 kg) (45°C) / 15 min = (1.5 kg) (60°C) / t
3/min = 90 / t
t = 30 min
Answer:
2682
Explanation:
Work done is given by :
Work = Force x distance
= mg x d
So, work done in lifting the box of 23 kg up to my waist of 1 m high is :
W = mg x d
= 23 x 9.18 x 1
= 211.14
Now work done carrying the box horizontally 6 meters across the room is
W = mg x d
= 23 x 9.18 x 6
= 1266.84
Work done in placing the box on the shelf that is 5.7 m above the ground is
W = mg x d
= 23 x 9.18 x 5.7
= 1203.49
So the total work done is = 211.14 + 1266.84 + 1203.49
= 2681.47
= 2682 (rounding off)
Answer:
The impulse on the object is 60Ns.
Explanation:
Impulse is defined as the product of the force applied on an object and the time at which it acts. It is also the change in the momentum of a body.
F = m a
F = m(
)
⇒ Ft = m(
- 
)
where: F is the dorce on the object, t is the time at which it acts, m is the mass of the object, is its initialvelocity and is the final velocity of the object.
Therefore,
impulse = Ft = m( - )
From the question, m = 3kg, = 0m/s and = 20m/s.
So that,
Impulse = 3 (20 - 0)
= 3(20)
= 60Ns
The impulse on the object is 60Ns.
1 and A
2 and B
3 and D
4 and C
The answer is true. The blowing fan force the hot air to go through the process of convection .
