Answer:
69.74 N
Explanation:
We are given that
Weight of sled=49 N
Coefficient of kinetic friction
Weight of person=585 N
Total weight==mg=49+585=634 N
We know that
Force needed to pull the sled across the snow at constant speed,F=Kinetic friction
Where N= Normal=mg
Hence, the force is needed to pull the sled across the snow at constant speed=69.74 N
Answer:
a) 39.6 m/s b) 4123 N
Explanation:
a) At the top of the loop, all of the forces point downwards (force of gravity and normal force).
Fnet=ma
ma=m(v^2/R) (centripetal acceleration)
mg=m(v^2/R)
m cancels out (this is why pilot feels weightless) so,
g=(v^2/R)
9.8 m/s^2 = v^2/160 m
v^2=1568 m^2/s^2
v=39.6 m/s
b) At the bottom of the loop, the normal force and the force of gravity point in opposite directions. The normal force is the weight felt.
Convert 300 km/hr to m/s
300 km/hr=83.3 m/s
Convert pilot's weight into mass:
760 N = 77.55 kg
Fnet=ma
n-mg=m(v^2/R)
n=(77.55 kg)(((83.3 m/s)^2)/160 m)+(77.55 kg)(9.8 m/s^2)
n=3363.2 N+760 N=4123 N
Answer:
0.37sec
Explanation:
Period of oscillation of a simple pendulum of length L is:
T
=
2
π
×
√
(L
/g)
L=length of string 0.54m
g=acceleration due to gravity
T-period
T = 2 x 3.14 x √[0.54/9.8]
T = 1.47sec
An oscillating pendulum, or anything else in nature that involves "simple harmonic" (sinusoidal) motion, spends 1/4 of its period going from zero speed to maximum speed, and another 1/4 going from maximum speed to zero speed again, etc. After four quarter-periods it is back where it started.
The ball will first have V(max) at T/4,
=>V(max) = 1.47/4 = 0.37 sec
Answer:
The mechanical advantage of the system is 8
Explanation:
the mechanical advantage measures how much the system multiplies the input force to get the output.
In the given:
The input force (effort) is 20 Newton
The output force (load) is 160 Newton
This means that the mechanical advantage is:
mechanical advantage = load / effort = 160 / 20 = 8
Note that the mechanical advantage is unit-less (has no unit) since it is a ratio between two forces.
Hope this helps :)
Consider 20 deg.C. as room temperature.
From tables,
Silver has a resistivity of 1.6*10^-8 ohm-m at 20 deg.C, and it increases by 0.0038 ohm-m per deg.K increase.
Therefore if the temperature rise above 20 deg.C is T, then silver will have resistivity of
1.6*10^-8(1 + 0.0038T) ohm-m
At room temperature, the resistivity of tungsten (from tables) is 5.6*10^-8.
The resistivity of silver will be 4 times that of tungsten (at room temperature) when
1.6*10^-8(1 + 0.0038T) = 4*5.6*10^-8
1 + 0.0038T = 14
T = 13/.0038 = 3421 deg.K approx
Answer: 20 + 3421 = 3441 °C
