Answer:
Explanation:
mass, m = 1 kg
Position (2, 3 ) m
height, h = 2 m
acceleration due to gravity, g = 9.8 m/s^2
Here, no force is acting in horizontal direction, the force of gravity is acting in vertical direction, so the work done by the gravitational force is to be calculated.
Force mass x acceleration due to gravity
F = 1 x 9.8 = 9.8 N
Work = force x displacement x CosФ
Where, Ф be the angle between force vector and the displacement vector.
Here the value of Ф is 180° as the force acting vertically downward and the displacement is upward
So, W = 9.8 x 2 x Cos 180°
W = - 19.6 J
Thus, option (A) is correct.
The Volume of a Cube with a side(s) of 11.4 cm is
<span>V = s^3 </span>
<span> V = (11.4)^3 cm^3 </span>
<span> V = 1481.544 cm^3 </span>
<span> V = 1482 cm^3</span>
<span>however the Surface Area of a cube is the combined area of all the sides </span>
<span> A = 6s^2 </span>
<span> A = 6(11.4)^2 cm^2 </span>
<span> A = 779.76 cm^2 </span>
I think it is B Because it sounds like the best choice
Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).
Explanation:
Kinetic energy of the hammer ,K.E.=
Half of the kinetic energy of the hammer is transformed into heat in the nail.
Energy transferred to the nail in one blow =
Total energy transferred after 3 blows,Q =
Mass of the nail = 15 g = 0.015 kg
Change in temperature =
Specif heat of the steel = c = 448 J/kg K
The increase in temperature of the nail after the three blows is 8.1 Kelvins.Hence, correct option is (d).
Answer: 3.84dB
Explanation:
Since person A is talking 1.2dB louder than B, we will have
A = 1.2B... (1)
Similarly, person C is talking 3.2 dB louder than person A, we have
C = 3.2A... (2)
From equation 1, B = A/1.2... (3)
To get the ratio of the sound intensity of person C to the sound intensity of person B, we will divide equation 2 by 3 to give
C/B = 3.2A/{A/1.2}
C/B = 3.2A×1.2/A
C/B = 3.2×1.2
C/B = 3.84dB
