Change the Subject
Make h the subject of A=1/2bh
h=2A/b
A car is travelling at 70 km/h and the reaction time of the driver is 0.50 seconds. Find the stopping distance of this car using the formula d=5Vt/18+v^2/170.
39 m
Evaluate P if P=2l+2b and l=30 and b=21.
TRUE or FALSE: The main idea of solving equations is to get the variable by itself.
TRUE
Solve: 3x-7=11
x=6
Make w the subject of the equation u=-5w+v
w=(v-u)/5
Use the formula A=crt(4B/2pi) to find the value of A when B=20.
A = 2.34
The circumference of a circle is given by the formula C=2pir where C is the circumference and r is the radius. Evaluate the circumference of a circle with radius 14 cm.
87.96 cm
Solve: 9-3/4x=57
x=-64
Solve: 6x+8= 50
X=8
Make sinC the subject of the formula A=1/2absinC
sinC=2A/ab
Levi weighs 74 kg and consumes 5 standard drinks in an hour. Calculate Levi's blood alcohol content. (BAC=(10N-7.5H)/6.8M)
BAC=0.084
How long will it take a vehicle to travel 342 km at a speed of 70 km/h?
4.89 h
Solve: d/2+5=4d+2
d=6/7
Solve: 3-2s=3s+12
s=-9/5
The formula v^2=u^2+2as is used to relate acceleration, velocity and distance. Make s the subject of the formula.
s=(v^2-u^2)/2a
The kinetic energy K (joules) of a particle of mass m kg with a velocity of v m/s, is given by the formula K=1/2mv^2. Find m when K=5.2 joules and v=2 m/s.
m=2.6 kg
A landscaper charges $120 up front and $65 for each hour, h, that he works. Write a linear equation for the total charge, C, of any job.
C=120+65h
Solve: 9(1-3a)=21
a=-4/9
Solve 7(x+4)=15
x=-13/7
The formula v^2=u^2+2as is used to relate acceleration, velocity and distance. Make u the subject of the formula.
u=sqrt(v^2-2as)
The kinetic energy K (joules) of a particle of mass m kg with a velocity of v m/s, is given by the formula K=1/2mv^2. Find v when K=6.4 joules and m=1.3 kg.
v=3.138 m/s
Anna and Bridget live 33 km apart. They cycle to meet each other. Anna travels at 10 km/h and Bridget travels at 12 km/h. How long until they meet each other?
1.5 h
Solve x/2+x/6=1
x=3/2
Solve: 1/3(5u+7)=4
u=1