amount of heat is removed to lower the temperature of 80 grams of water from 75ºC to 45ºC with specific heat of liquid water is 4.18 J/gºC
= 4.18 J/gºC * 80g * (75-45)ºC
= 10032J
Answer:
5 mm
Explanation:
Youngs's modulus (Y) is described by the following expression:
Where F is the force exerted on the tendon, L is its length, A is its area and ΔL is its change in length (stretching).
The force in this case is 8 times the weight of the runner:
Therefore, the change in length of the tendon is given by:
the runner's Achilles tendon will stretch by 0.004989 m, which is roughly 5 mm.
Answer:
d) is the same as when it started from rest
Explanation:
using equation of motion
v = u + at
second law of momentum defines
F = ma
a = F /m
the equation becomes
v = u + (F/m)t
from hear
since v is directly proportional to the force and the force remain the same, the increase in the cart speed will also remain the same.
Answer: momentum has the same direction as that of velocity but when 2 bodies with the same linear momentum & different velocities it has different masses because a vector quantity is represented by a cross product of mass and velocity of object .
Answer:
ΔT = 40.91 °C
Explanation:
First we find the kinetic energy of one hit to the nail:
K.E = (1/2)mv²
where,
K.E = Kinetic energy = ?
m = mass of hammer = 1.6 kg
v = speed of hammer = 7.7 m/s
Therefore,
K.E = (1/2)(1.6 kg)(7.7 m/s)²
K.E = 47.432 J
Now, for 10 hits:
K.E = (10)(47.432 J)
K.E = 474.32 J
Now, we calculate the heat energy transferred (Q) to the nail. As, it is the 59% of K.E. Therefore,
Q = (0.59)K.E
Q = (0.59)(474.32 J)
Q = 279.84 J
The change in energy of nail is given as:
Q = mCΔT
where,
m = mass of nail = 7.6 g = 0.0076 kg
C = specific heat capacity of aluminum = 900 J/kg.°C
ΔT = Increase in temperature = ?
Therefore,
279.84 J = (0.0076 kg)(900 J/kg.°C)ΔT
ΔT = (279.84 J)/(6.84 J/°C)
<u>ΔT = 40.91 °C</u>