Answer:
139.6m/s
Explanation:
Calculate the tension first, T=m*g
mass(m): 1750kg, gravity(g): 9.8m/s^2
T= 1750*9.8
=17150N
Then calculate the wave speed using the equation v = √ (T/μ)
v= √(17150N)/(0.88kg/m)
=139.6m/s
Answer:
Speed of the ball relative to the boys: 25 km/h
Speed of the ball relative to a stationary observer: 35 km/h
Explanation:
The RV is travelling at a velocity of

Here we have taken the direction of motion of the RV as positive direction.
The boy sitting near the driver throws the ball back with speed of 25 km/h, so the velocity of the ball in the reference frame of the RV is

with negative sign since it is travelling in the opposite direction relative to the RV. Therefore, this is the velocity measured by every observer in the reference frame of the RV: so the speed measured by the boys is
v = 25 km/h
Instead, a stationary observer outside the RV measures a velocity of the ball given by the algebraic sum of the two velocities:
v = +60 km/h + (-25 km/h) = +35 km/h
So, he/she measures a speed of 35 km/h.
Changing the medium of the wave.
Waves is always determined by the properties of the medium, which means that changing the medium will change the velocity of the wave
Answer:
The size of the force developing inside the steel rod is 32039.28 N
Explanation:
Given;
length of the steel rod, L = 1.55 m
cross sectional area of the steel, A = 4.89 cm²
temperature change, ∆T = 28.0 K
coefficient of linear expansion for steel, α = 1.17 × 10⁻⁵ 1/K
Young modulus of steel, E = 200.0 GPa.
Extension of the steel is given as;
α ∆T L = FL / AE
α ∆T = F/AE
F = AEα ∆T
F = ( 4.89 x 10⁻⁴)(200 x 10⁹)(1.17 × 10⁻⁵)(28.0 K)
F = 32039.28 N
Therefore, the size of the force developing inside the steel rod when its temperature is raised, is 32039.28 N