Answer:
45km/hr
Explanation:
Total distance=450km
Total speed=50km/hr
Total time= distance/speed
=450/50
=9hrs
distance a=180km
speed a=60km/hr
Time a=180/60
=3hrs
Distance b=450-180=270km
Speed b=?
Time b=270/speed b
Total time=time a + time b
9=3+(270/speed b)
270/speed b =9-3
270/speed b =6
6*speed b =270
Speed b=270/6
Speed b=45km/hr
Answer:
Explanation:
Length if the bar is 1m=100cm
The tip of the bar serves as fulcrum
A force of 20N (upward) is applied at the tip of the other end. Then, the force is 100cm from the fulcrum
The crate lid is 2cm from the fulcrum, let the force (downward) acting on the crate be F.
Using moment
Sum of the moments of all forces about any point in the plane must be zero.
Let take moment about the fulcrum
100×20-F×2=0
2000-2F=0
2F=2000
Then, F=1000N
The force acting in the crate lid is 1000N
Option D is correct
Answer:
Speed of 1.83 m/s and 6.83 m/s
Explanation:
From the principle of conservation of momentum
where m is the mass, 
is the initial speed before impact, 
and 
are velocity of the impacting object after collision and velocity after impact of the originally constant object
Therefore 
After collision, kinetic energy doubles hence
Substituting 5 m/s for then
Also, it’s known that hence 
Solving the equation using quadratic formula where a=2, b=-10 and c=-25 then 
Substituting, 
Therefore, the blocks move at a speed of 1.83 m/s and 6.83 m/s
Answer:
Explanation:
Electric field strength= Force/unit charge
E= (kQq/r²)/q ₓ r
where r is the unit vector in the direction of unit charge
E=
The output of the machine is
(output work) = (output force) x (distance)
450 N-m = (output force) x (3 meters)
Divide each side
by 3 meters: Output force = (450 N-m) / (3 m)
= 150 newtons .
With all the information given about the output work, we don't need
to know anything about the input work, or even the fact that we're
dealing with a machine.
It's comforting, though, to look back and notice that the output work
(450 N-m) is not more than the input work (500 N-m). So everything
is nice and hunky-dory.
___________________________________
Well, my goodness !
I didn't even need to go through all of that.
Given:
-- The input force to the machine is 50 newtons.
-- The mechanical advantage of the machine is 3 .
That right there tells us that
-- The output force of the machine is 150 newtons.
We don't need any of the other given information.
