The box is in equilibrium, so Newton's second law says
<em>n</em> + (-<em>w</em>) = 0
65 N + (-<em>f</em> ) = 0
where <em>n</em> denotes the magnitude of the normal force, <em>w</em> denotes the weight of the box, and <em>f</em> denotes the magnitude of the friction force.
The box has a weight of
<em>w</em> = (25 kg) (9.80 m/s²) = 245 N
so <em>n</em> = 245 N, too.
The friction force has magnitude
<em>f</em> = 65 N
and is proportional to the normal force by a factor of <em>µ</em>, the coefficient of kinetic friction. So we have
65 N = <em>µ</em> (245 N) → <em>µ</em> ≈ 0.26
The element Nitrogen is
usually present in almost all proteins, and it also forms strong bonds due to
its ability to form a triple bond with its self, also to other elements.
<span>The nitrides use a variety
of different oxidation and almost all the oxides forms gasses are at 25 degrees
Celsius. The oxide of nitrogen are acidic, thus, easily attaching protons.</span>
Answer:
a) t=1s
y = 10.1m
v=5.2m/s
b) t=1.5s
y =11.475 m
v=0.3m/s
c) t=2s
y =10.4 m
v=-4.6m/s (The minus sign (-) indicates that the ball is already going down)
Explanation:
Conceptual analysis
We apply the free fall formula for position (y) and speed (v) at any time (t).
As gravity opposes movement the sign in the equations is negative.:
y = vi*t - ½ g*t2 Equation 1
v=vit-g*t Equation 2
y: The vertical distance the ball moves at time t
vi: Initial speed
g= acceleration due to gravity
v= Speed the ball moves at time t
Known information
We know the following data:
Vi=15 m / s
t=1s ,1.5s,2s
Development of problem
We replace t in the equations (1) and (2)
a) t=1s
=15-4.9=10.1m
v=15-9.8*1 =15-9.8 =5.2m/s
b) t=1.5s
=22.5-11.025=11.475 m
v=15-9.8*1.5 =15-14.7=0.3m/s
c) t=2s
= 30-19.6=10.4 m
v=15-9.8*2 =15-19.6=-4.6m/s (The minus sign (-) indicates that the ball is already going down)
Answer:
u = - 38.85 m/s^-1
Explanation:
given data:
acceleration = 2.10*10^4 m/s^2
time = 1.85*10^{-3} s
final velocity = 0 m/s
from equation of motion we have following relation
v = u +at
0 = u + 2.10*10^4 *1.85*10^{-3}
0 = u + (21 *1.85)
0 = u + 38.85
u = - 38.85 m/s^-1
negative sign indicate that the ball bounce in opposite directon