Answer:
Explanation:
Magnitude of frictional force = μ mg
μ is either static or kinetic friction.
To start the crate moving , static friction is calculated .
a ) To start crate moving , force required = μ mg where μ is coefficient of static friction .
force required =.517 x 56.6 x 9.8 = 286.76 N .
b ) to slide the crate across the dock at a constant speed , force required
= μ mg where μ is coefficient of kinetic friction , where μ is kinetic friction
= .26 x 56.6 x 9.8 = 144.21 N .
Answer : The momentum of ball is, 15 kg.m/s
Explanation :
Momentum : It is defined as the motion of a moving body. Or it is defined as the product of mass of velocity of an object.
Formula of momentum is:
where,
p = momentum = ?
m = mass = 1.5 kg
v = velocity = 10 m/s
Now put all the given values in the above formula, we get:
Therefore, the momentum of ball is 15 kg.m/s
Answer:
The liquid phase will have the lowest temperature change upon heating.
Explanation:
Assuming no phase change due to heating, we know that the temperature change, is proportional to the mass heated, being the proportionality constant a quantity that depends on the material, and represents the resistance of the material to change the temperature, called specific heat.
So, if we assume that the mass is the same for the three phases, and that the amount of heat supplied is also the same,the phase with the highest specific heat will have the lowest temperature change.
So, the liquid phase will be the one that exhibits this behavior, as the specific heat of liquid water (4.184 J/gºC) is the highest among the three phases.
Answer:
103.5 meters
Explanation:
Given that a stunt person has to jump from a bridge and land on a boat in the water 22.5 m below. The boat is cruising at a constant velocity of 48.3 m/s towards the bridge. The stunt person will jump up at 6.45 m/s as they leave the bridge.
The time the person will jump to a certain spot under the bridge can be calculated by using the formula below:
h = Ut + 1/2gt^2
since the person will fall under gravity, g = 9.8 m/s^2
Also, let assume that the person jump from rest, then, U = 0
Substitute h, U and g into the formula above
22.5 = 1/2 * 9.8 * t^2
22.5 = 4.9t^2
22.5 = 4.9t^2
t^2 = 22.5/4.9
t^2 = 4.59
t = 
t = 2.143 seconds
From definition of speed,
speed = distance /time
Given that the boat is cruising at a constant velocity of 48.3 m/s towards the bridge, substitute the speed and the time to get the distance.
48.3 = distance / 2.143
distance = 48.3 * 2.143
distance = 103.5 m
Therefore, the boat should be 103.5m away from the bridge at the moment the stunt person jumps?
