Explanation :
A circuit is the representation of the path of the flow of current. The circuit can be either closed or open.
When the switch is off the circuit is closed circuit and when the switch is not connected the circuit is open.
The items that are sufficient to make a circuit are as follows :
- Voltage source like a battery.
- Resistors or electrical equipment like heater, motor etc.
Other components can be ammeter, voltmeter, ac source, variable resistors etc.
Answer:

Explanation:
From the question we are told that:
Force P=88Ib
Mass of crate M_c=210Ib
Generally the equation for Frictional force F is mathematically given by


with 

Therefore since Static Friction supersedes applied force body remains at rest.
Frictional force =88Ib (negative)

Explanation:
Speed is the rate of change of distance with time. It is a scalar quantity with magnitude both no direction.
Speed =
The unit is m/s or km/hr or mile/hr
Distance covered is simply the length of the path traveled.
The unit is m or km or miles
Time taken is the duration of an event.
The unit is seconds or minutes or hour.
Pressure is the amount of force per unit area. In formula it
is,
P = F ÷ A
P = 7000 N ÷ 0.4 m2
P = 17,500 N/m2
The amount of pressure the truck exerts on the piston is
17,500 N/m2