Answer:
Explanation:
mass of box, m = 60 kg
distance, d = 6.2 m
force, P = 150 N
coefficient of kinetic friction, μk = 0.21
work done by the gravitational force, Wg = Force x distance x cos 90
Wg = 0 J
Work done by the normal force, Wn = force x distance x Cos 90
Wn = 0 J
Work done by the friction force, Wf = - μk mg d
Wf = - 0.21 x 60 x 9.8 x 6.2 = - 765.58 J
Work done by the applied force, Wp = P x d
Wp = 150 x 6.2 = 930 J
Answer:
d_{b} = 2 d_{a}
Explanation:
The electrical resistance for a cylindrical wire is described by the expression
R = ρ L / A
The area of a circle is
A = π r²
r = d / 2
A = π d²/4
We substitute
R = ρ L 4 /π d²
Let's apply this expression to our case, they indicate that the resistance of wire A is 4 times the resistance of wire B
= 4 R_{b}
We substitute
ρ 4/π
² = 4 (ρ 4/π d_{b}²)
1 / d_{a}² = 4 / d_{b}²
d_{a} = d_{b} / 2
Answer:
Power will be 0.2023 watt
And when amplitude is halved then power will be 0.0505 watt
Explanation:
We have given mass of the Piano wire m = 2.60 gram = 0.0026 kg
Length of wire l = 84 cm = 0.84 m
So mass density 
Tension in the wire T = 25 N
Frequency f = 120 Hz
So angular frequency 
And amplitude A = 1.6 mm = 0.0016 m
We have to find the generated power
Power is given by 
From the relation we can see that power 
So if amplitude is halved then power will be
times
So power will be equal to 
Here we have mass that moves at ceratin speed. This means that we have momentum. The law that must be observed is law of conservation of momentum. It states that momentum before certain event is equal to a momentum after that event. Here we have three masses so we can write this as:

Before the firecracker blows a coconut does not move, so left side is equal to 0:

We know that m1=m2=m and m3=2m. Also we are asked to find v3f so we can rewrite formula:

We must take in consideration that two parts with same mass do not move in same direction. The center of mass of these two parts moves between them at angle of 45° with respect to both south and west. The speed of a center of mass is:

This speed we can insert into formula for v3f:

We can see that part of a coconut with biggest mass has same speed as center of mass of two other parts. Negative sign shows that direction is opposite to direction of two pats. Biggest part moves towards north-east.
Answer:
-6 m/s²
Explanation:
Given:
v₀ = 50 m/s
v = 20 m/s
t = 5 s
Find: a
v = at + v₀
20 m/s = a (5 s) + 50 m/s
a = -6 m/s²