Answer:
a)15 N
b)12.6 N
Explanation:
Given that
Weight of block (wt)= 21 N
μs = 0.80 and μk = 0.60
We know that
Maximum value of static friction given as
Frs = μs m g = μs .wt
by putting the values
Frs= 0.8 x 21 = 16.8 N
Value of kinetic friction
Frk= μk m g = μk .wt
By putting the values
Frk= 0.6 x 21 = 12.6 N
a)
When T = 15 N
Static friction Frs= 16.8 N
Here the value of static friction is more than tension T .It means that block will not move and the value of friction force will be equal to the tension force.
Friction force = 15 N
b)
When T= 35 N
Here value of tension force is more than maximum value of static friction that is why block will move .We know that when body is in motion then kinetic friction will act on the body.so the value of friction force in this case will be 12.6 N
Friction force = 12.6 N
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.
Still go straight but would obviously go up in speed!!
Hope this helps plz mark as brainlist and 5 star
Given Information:
slope angle = θ = 30°
spring constant = k = 30 N/m
compressed length = x = 10 cm = 0.10 m
mass of ice cube = m = 63 g = 0.063 kg
Required Information:
distance traveled by ice cube = d = ?
Answer:
distance traveled by ice cube = 0.48 m
Explanation:
Using the the principle of conversation of energy, the following relation holds true for this case,
mgh = 1/2*kx²
h = 1/2*kx²/mg
Where h is the height of the slope, m is the mass of ice cube, k is the spring constant and x is the compressed length o the spring and g is gravitational acceleration.
h = 1/2*kx²/mg
h = 1/2*30(0.1)²/0.063*9.8
h = 0.242 m
From trigonometry ratio,
sinθ = h/d
d = h/sinθ
d = 0.242/sin(30)
d = 0.48 m
Therefore, when the ice cube is released, it will travel a total distance 0.48 up the slope before reversing direction.
