Answer:
u = 25 m/s
Explanation:
given,
length of skid = 93 m
coefficient of friction = 0.35
final velocity = 0 m/s
initial velocity = ?
force here is friction f = μ mg
F = ma
now com paring
-μ mg = m a
a = - μ g
a = - 0.35 x 9.8
a = -3.43 m/s²
we know,
v² = u² + 2 a s
0 = u² - 2 x 3.43 x 93
u² = 637.98
u = 25.26 m/s
u = 25 m/s (two significant figure)
Answer:
a) The student feel light
b) Nbottom = 758 N
c) N'top= 236 N
d) N'bottom= 1055 N
Explanation:
a) W= 659N , Ntop= 560N
W > Ntop ---> Student feel less weight
b) Top:
∑F= W - Ntop = m.v²/R
m.v²/R = 659N - 560 N = 99 N
Bottom:
∑F= Nbottom- W = m.v²/R
Nbottom= W + m.v²/R = 659N + 99 N = 758N
c) W= 659 N , Ntop= 560 N , v'=2.v
N'top= ?
∑F= W - N'top = m.v'²/R
N'top= W - 4.m.v²/R
N'top = 659 N - 4. 99 N = 263 N
d) N'bottom = ?
∑Fbottom= N'bottom- W = m.v'²/R
N'bottom = W + 4.m.v²/R = 659 N + 4. 99 N = 1055 N
Answer:
Fa=774 N
Fb=346 N
Explanation:
We will solve this problem by equating forces on each axis.
- On x-axis let forces in positive x-direction be positive and forces in negative x-direction be negative
- On y-axis let forces in positive y-direction be positive and forces in negative y-direction be negative
While towing we know that car is mot moving in y-direction so net force in y-axis must be zero
⇒∑Fy=0
⇒
⇒
⇒
Given that resultant force on car is 950N in positive x-direction
⇒∑Fx=950
⇒
⇒
⇒
⇒
⇒
⇒ 
⇒


Therefore approximately, Fa=774 N and Fb=346 N
Answer:
Work is done by the heart on the blood during this time is 0.04 J
Explanation:
Given :
Mass of blood pumped, m = 80 g = 0.08 kg
Initial speed of the blood, u = 0 m/s
Final speed of the blood, v = 1 m/s
Initial kinetic energy of blood is determine by the relation:

Final kinetic energy of blood is determine by the relation:

Applying work-energy theorem,
Work done = Change in kinetic energy
W = E₂ - E₁

Substitute the suitable values in the above equation.

W = 0.04 J
This instrument is called a spring scale.