Answer:
option (c) is correct
Explanation:
Half life of a substance is the time in which the element becomes half of is initial value.
half life, T = 8 days
Amount remaining, N = 10 % of original value
Let the original value is No.
N = 10% of No
N = 0.1 No
Let the time taken is t and the decay constant is λ.
The relation between the decay constant and the half life is given by
Us the equation of radioactivity
Taking natural log on both the sides, we get
0.08664 t = 2.303
t = 26.6 days
One is for far distance the other is for close range
Ferromagnetic, paramagnetic, and diamagnetic
Given that.
F=3•i+4•j
And it from point (0,0)m to (5,6)m
dx=final position - initial position
dx=(5,6)-(0,0)
dx=(5,6)m
dx=5•i +6•j
Work done by the force is give by
W = F•dx
W=F•dx
Note that i•i=j•j=1 and i•j=j•i=0
Then,
W=(3i+4j)•(5i+6j)
Therefore,
W=3i•(5i+6j)+4j•(5i+6j)
W=15i•i+18i•j+20j•i+24j•j
W=15+0+0+24
W=39J
Then the work done by the force is 39 Joules
Answer:
θ = 8.50°
To the nearest angle
θ = 9.0°
the golfer must hit the ball at angle 9° so that it travels 120 feet.
Explanation:
The range of a projectile is the horizontal distance covered by a projectile, which can be written as;
r = (u^2× sin2θ)/g
Where;
r = range
u = initial speed
θ = angle from horizontal
g = acceleration due to gravity
Solving for θ,
sin2θ = rg/u^2
θ = 1/2 × sin⁻¹(rg/u^2) ....1
Given;
r = 120 ft
u = 115 ft/s
g = 9.81m/s = 32.2 ft/s
Substituting the values into the equation 1;
θ = 1/2 × sin⁻¹(120×32.2/115^2)
θ = 1/2 × sin⁻¹(0.29217)
θ = 1/2 × 17.00
θ = 8.50°
To the nearest angle
θ = 9.0°
